Delaware County, PA: risk-assessment baseline packet, release 2026-10

Summary

Plan status as of 2026-09-30: No county-level plan row in FEMA data.

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($73,868,895 a year), Earthquake ($13,263,729) and Heat Wave ($12,832,470).

The tables that follow are organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B (B1-a to B2-c); each heading says which item its tables support.

Terms used

EAL:: expected annual loss: FEMA's modeled average yearly loss from a hazard.
NRI:: FEMA's National Risk Index (version 1.20, December 2025).
NFIP:: National Flood Insurance Program.
RL, SRL:: repetitive loss and severe repetitive loss: flood-insured properties with repeated claims (definitions in B2-c).
FMA, HMGP:: Flood Mitigation Assistance and Hazard Mitigation Grant Program, FEMA mitigation grants.
PA:: FEMA Public Assistance: disaster aid to governments and some nonprofits.
Zone-level:: NOAA logged the event for a National Weather Service forecast zone, which may include parts of neighboring counties.
County-coded:: NOAA logged the event to this county.
FIPS:: the federal code for a place; 42045 is this area.
D0 to D4:: U.S. Drought Monitor categories, from abnormally dry (D0) to exceptional drought (D4).
F/EF, EFU:: Fujita and Enhanced Fujita tornado ratings; EFU is an unrated tornado.
kt, CONUS:: knots (1 kt is about 1.15 mph); the contiguous United States.
CFR:: Code of Federal Regulations.
A4-a, E1-a:: other items of FEMA's Local Mitigation Plan Review Tool (sources, and changes since the last plan).
Dollars:: nominal (as reported, labeled with the year), not adjusted for inflation.

Plan clock

No county-level plan row in FEMA data

What changed since your last plan

Not available. No county-level plan row in FEMA data, so there is no approval date to count from.

Sources: 1, 2, 4, 6 (numbered list at the end)

Plan status for every jurisdiction listed in this county: 50 rows, in the section "Plan clock: Plan status for every jurisdiction listed in this county" on the following pages.

State plan status and tribal plans in this state: see the state page.

Plan clock

Plan status for every jurisdiction listed in this county

Source: 1

Jurisdiction	Type	Status	Plan	Approved	Expires	Days to expirynegative = days since expiry	Update underway	Notes
Aldan borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Brookhaven borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-05-01
Chester city	City	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-08
Chester Heights borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-06
Clifton Heights borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Collingdale borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Colwyn borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Darby borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-15
East Lansdowne borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Eddystone borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Folcroft borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Glenolden borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Lansdowne borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2024-09-04
Marcus Hook borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-06
Media borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-05-18
Millbourne borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Morton borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Norwood borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Parkside borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Prospect Park borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-14
Ridley Park borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Rose Valley borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Rutledge borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Sharon Hill borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Swarthmore borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Trainer borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Upland borough	Organized Borough	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-14
Yeadon borough	Organized Borough	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Aston township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-05-17
Bethel township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-04-03
Chadds Ford township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2024-04-03
Chester township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	Delaware County Hazard Mitigation Plan (FEMA plan 108724), pending adoption here	2023-02-27 by FEMA; not yet adopted here	2028-02-26 once adopted		FEMA tracker shows a plan approvable pending adoption	Not yet eligible: adopt the approved plan.
Concord township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-07
Darby township	Township	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Edgmont township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2024-04-09
Haverford township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	Delaware County Hazard Mitigation Plan (FEMA plan 108724), pending adoption here	2023-02-27 by FEMA; not yet adopted here	2028-02-26 once adopted		FEMA tracker shows a plan approvable pending adoption	Not yet eligible: adopt the approved plan.
Lower Chichester township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2024-01-02
Marple township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-13
Middletown township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress
Nether Providence township	Township	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Newtown township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress
Radnor township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-04-24
Ridley township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-22
Springfield township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-07-11
Thornbury township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-01
Tinicum township	Township	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Upper Chichester township	Township	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-09
Upper Darby township	Township	No approved plan on record	none	none	none		FEMA tracker shows a plan in progress
Upper Providence township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	Delaware County Hazard Mitigation Plan (FEMA plan 108724), pending adoption here	2023-02-27 by FEMA; not yet adopted here	2028-02-26 once adopted		FEMA tracker shows a plan approvable pending adoption	Not yet eligible: adopt the approved plan.
Brandywine Conservancy & Museum Special District	Special District	Approved, expires 2028-02-26	Delaware County Hazard Mitigation Plan (FEMA plan 108724)	2023-02-27	2028-02-26	514	FEMA tracker shows a plan in progress	this jurisdiction approved 2023-03-13

Supports FEMA checklist item B1-a: hazard identification

Hazards NRI does not cover (local data needed)

dam failure (incl. upstream dams)
levee failure
flash flood as its own subtype
ice jams
debris flows
erosion (riverine and coastal)
land subsidence and sinkholes
expansive soils

The 18 National Risk Index hazards, ranked by expected annual loss (EAL)

Sources: 5, 6

Rank by EAL	Hazard	NRI risk rating	EAL rating	EAL buildingsmodeled dollars per year	EAL agriculturemodeled dollars per year	Cost of expected deaths and injuriesFEMA's dollar value per year, not property damage	EAL total (see note)modeled dollars per year	Storm Events records, 1996 to 2026-06-30count	Storm Events coverage note
1	Inland Flooding	Relatively High	Relatively High	$72,491,995	$3,352	$1,373,549	$73,868,895	220
2	Earthquake	Relatively Moderate	Relatively Moderate	$9,147,333	n/a	$4,116,397	$13,263,729		Storm Events does not record earthquakes.
3	Heat Wave	Relatively High	Relatively High	$8	$157	$12,832,305	$12,832,470	103
4	Tornado	Relatively High	Relatively High	$4,941,096	$140	$4,463,139	$9,404,375	2
5	Cold Wave	Relatively High	Relatively High	$1,597	$4	$8,510,938	$8,512,539	30	Includes 1 Frost/Freeze record (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor).
6	Hurricane	Relatively Moderate	Relatively Moderate	$5,627,996	$46,911	$180,145	$5,855,053	3
7	Strong Wind	Relatively High	Relatively High	$1,824,232	$2,502	$3,358,606	$5,185,341	421	Includes 38 High Wind and 101 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
8	Winter Weather	Very High	Very High	$608,737	$4	$1,531,182	$2,139,923	212	Includes 4 Sleet records (outside NRI's Winter Weather definition).
9	Lightning	Relatively High	Relatively High	$117,552	n/a	$2,015,701	$2,133,253	39
10	Ice Storm	Relatively High	Relatively High	$425,926	n/a	$324,042	$749,969	2
11	Coastal Flooding	Relatively Moderate	Relatively Moderate	$723,470	n/a	$6,696	$730,166	55
12	Drought	Relatively Low	Relatively Low	n/a	$208,692	n/a	$208,692	44
13	Hail	Very Low	Very Low	$30,309	$13,347	$2,127	$45,783	53
14	Wildfire	Very Low	Very Low	$10,313	$1	$2,697	$13,011	3
15	Landslide	Very Low	Very Low	$2,624	n/a	$135	$2,758	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
16	Avalanche	Very Low	Very Low	$0	n/a	$11	$11	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
	Tsunami	Insufficient Data	Insufficient Data	n/a	n/a	n/a	n/a	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).

Total = buildings + agriculture + population equivalence; FEMA values each expected death (or 10 injuries) at $13.7 million (2024 dollars).

NRI risk rating combines expected annual loss with social vulnerability and community resilience; EAL rating rates expected annual loss alone. Both compare this county with all U.S. counties.

Local data needed: state and local landslide and tsunami records (Storm Events records these hazards only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: volcanic activity. That is the evidence for leaving them out of the plan.

The state hazard mitigation plan also lists hazards for this county; FEMA asks the plan to explain any hazard it leaves out.

Supports FEMA checklist item B1-b: hazard location

Affects the whole county (national data give no location within it): Cold Wave, Drought, Hail, Heat Wave, Ice Storm, Lightning, Strong Wind and Winter Weather.

Coastal Flooding and Inland Flooding: The FEMA Flood Insurance Rate Map (FIRM) is the required location source for flooding. See the FEMA Flood Map Service Center (https://msc.fema.gov) for this county.

Hazards that vary within the county: highest-rated census tracts

Source: 5

Hazard	Highest-rated census tractsNRI risk rating, score 0 to 100
Avalanche	tract 4072.01 (Very Low, 5.0); tract 4101.01 (Very Low, 3.3)
Earthquake	tract 4107 (Relatively Moderate, 84.0); tract 4021 (Relatively Moderate, 81.4); tract 4028 (Relatively Moderate, 80.7)
Hurricane	tract 4107 (Relatively Moderate, 79.1); tract 4097.01 (Relatively Low, 77.9); tract 4099.02 (Relatively Low, 77.7)
Landslide	tract 4100 (Relatively Low, 87.4); tract 4102 (Relatively Low, 87.3); tract 4072.01 (Relatively Low, 85.3)
Tornado	tract 4108 (Relatively Moderate, 68.3); tract 4107 (Relatively Moderate, 67.0); tract 4097.01 (Relatively Moderate, 66.0)
Tsunami	no tract has a National Risk Index rating for this hazard
Wildfire	tract 4076 (Relatively Low, 69.3); tract 4029 (Relatively Low, 68.7); tract 4034.02 (Very Low, 67.4)

Up to 3 census tracts per hazard, highest National Risk Index rating first, then highest score; a tract number is the Census tract number (for example 4072.01 is Census Tract 4072.01). FEMA's Resilience Analysis and Planning Tool maps the National Risk Index for every tract: https://www.fema.gov/emergency-managers/practitioners/resilience-analysis-and-planning-tool

Supports FEMA checklist item B1-c: hazard extent

Extent: scale, observed range and worst recorded event per hazard

Sources: 6, 7

Hazard	Scale	Recordscount and years	Observed range	Worst recorded event	Most damaging (when different)	How it applies to jurisdictions	Note
Avalanche	none (count and damage only)	0
Coastal Flood, Storm Surge/Tide	none in data (flood depth: FIRM)	55 records, 1996 to 2024 (55 zone-level)		Coastal Flood, 2011-04-16, $50,000 property; $0 crops (2011 dollars); NWS zone PAZ070		Countywide (zone-level records).	Flood depth: see the FEMA Flood Insurance Rate Map.
Cold/Wind Chill, Extreme Cold/Wind Chill	wind chill	29 records, 1996 to 2022 (29 zone-level)	1 day to 16 days (median 1.5 days); 24 with a recorded value	16 consecutive days, 2003-01-14 to 2003-01-29, zone-level		Countywide (zone-level records).	Cold/Wind Chill records from May to September (a frost night, not a cold wave) are counted but not used for the longest run.
Frost/Freeze (outside NRI's Cold Wave definition)	crop damage	1 record, 2007 (1 zone-level)		No crop damage reported in 1 record.		Countywide (zone-level records).
Drought	U.S. Drought Monitor scale (D0 to D4)	44 records, 1997 to 2010 (44 zone-level)	1 day to 385 days (median 11 days); 18 with a recorded value	385 days (about 12.6 months), 2001-11-06 to 2002-11-25, a run of 13 consecutive Storm Events drought records, zone-level		Countywide (zone-level records).	Storm Events enters a drought at D2 or worse east of the Rockies and D3 or worse from the Rockies west (NWS Instruction 10-1605); NRI drought counts D3 and D4 only.
Earthquake	Modified Mercalli (local data)	0					Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail	hail size (inches)	63 records, 1957 to 2026	0.75 in to 1.75 in (median 1 in); 63 with a recorded value	1.75 in hail, 2010-06-24; same size also recorded on 1992-07-10, 2009-03-29		Event records naming jurisdictions in the plan: Rutledge borough (4 records), Sharon Hill borough (3 records), Media borough (2 records), Brookhaven borough (1 record), Chadds Ford township (1 record), East Lansdowne borough (1 record), Lansdowne borough (1 record), Marcus Hook borough (1 record), Morton borough (1 record), Swarthmore borough (1 record); and 2 more jurisdictions (see the Excel file).
Excessive Heat, Heat	heat index (in event narratives)	103 records, 1996 to 2026 (103 zone-level)	1 day to 10 days (median 3 days); 79 with a recorded value	10 consecutive days, 1999-07-23 to 1999-08-01, 1 direct death, zone-level		Countywide (zone-level records).	Heat records from November to March (unseasonable warmth, not a heat wave) are counted but not used for the longest run.
Hurricane, Tropical Storm, Tropical Depression	Saffir-Simpson	3 records, 2008 to 2020 (3 zone-level)		Strongest recorded: Tropical Storm record, 2011-08-27 to 2011-08-28, $500,000 property; $0 crops (2011 dollars); NWS zone PAZ070		Countywide (zone-level records).	Storm Events files every zone of a storm's episode under the storm's type; flooding from the storm is filed as Flood or Flash Flood records.
Ice Storm	Sperry-Piltz ice scale (local data)	2 records, 2011 to 2014 (2 zone-level)		No damage reported in 2 records.		Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flood	damage and flood days (flood depth: FIRM)	220 records, 1996 to 2026 (19 zone-level)		Flash Flood, 1999-09-16, $15,000,000 property; crops not reported (1999 dollars), 1 direct death, 14 direct injuries		Event records naming jurisdictions in the plan: Chadds Ford township (28 records), Chester city (10 records), Chester township (10 records), Marcus Hook borough (10 records), Brookhaven borough (9 records), Eddystone borough (8 records), Ridley Park borough (7 records), Trainer borough (7 records), Aldan borough (4 records), East Lansdowne borough (4 records); and 14 more jurisdictions (see the Excel file). Zone-level records (19) apply countywide.	Flood depth: see the FEMA Flood Insurance Rate Map. Storm Events damage is often $0 or blank for floods, major ones included; FEMA Public Assistance by declaration (B1-d) shows which floods cost the most.
Debris Flow	none (count and damage only)	0
Lightning	annualized frequency (the measure FEMA's Local Mitigation Planning Handbook names)	39 records, 1997 to 2017		Lightning, 2006-06-02, $0 property; $0 crops (2006 dollars), 1 direct death	Lightning, 2011-08-19, $250,000 property; $0 crops (2011 dollars)	Event records naming jurisdictions in the plan: Chester city (3 records), Chester township (3 records), Upper Darby township (3 records), Glenolden borough (2 records), Lansdowne borough (2 records), Darby borough (1 record), Darby township (1 record), Folcroft borough (1 record), Haverford township (1 record), Morton borough (1 record); and 5 more jurisdictions (see the Excel file).	Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)	wind speed (kt and mph)	139 records, 1996 to 2026 (139 zone-level)	35 kt (40 mph) to 55 kt (63 mph) (median 40 kt (46 mph)); 110 with a recorded value	55 kt (63 mph) measured gust, High Wind, 2011-02-25; NWS zone PAZ070	High Wind, 2003-09-18, $5,240,000 property; crops not reported (zone total, 2003 dollars)	Countywide (zone-level records).
Thunderstorm Wind	wind speed (kt and mph)	338 records, 1957 to 2026	40 kt (46 mph) to 91 kt (105 mph) (median 50 kt (58 mph)); 293 with a recorded value	91 kt (105 mph) estimated gust, Thunderstorm Wind, 2025-04-04	Thunderstorm Wind, 2015-06-23, $2,500,000 property; $0 crops (2015 dollars)	Event records naming jurisdictions in the plan: Media borough (16 records), Springfield township (11 records), Chadds Ford township (9 records), Chester city (9 records), Chester township (9 records), Radnor township (8 records), Folcroft borough (7 records), Brookhaven borough (6 records), Chester Heights borough (6 records), Darby borough (6 records); and 21 more jurisdictions (see the Excel file).
Tornado	Enhanced Fujita (Fujita before Feb 2007)	5 records, 1973 to 2019	F/EF0 to F/EF2 (median F/EF1); 5 with a recorded value	EF2 tornado, 2019-10-31, 0.47 mi within this county, 250 yd wide, damage not reported, 2 direct injuries	Tornado, 1993-09-27, $5,000,000 property; crops not recorded (1993 dollars)	Event records naming jurisdictions in the plan: Chester city (1 record), Chester township (1 record), Springfield township (1 record), Trainer borough (1 record).	Before 1996 a tornado is listed once, under the county where it began, with its whole path's rating and length; from 1996 on, each county lists its own segment. Length is not used to rank tornadoes (see Methods).
Tsunami	none (count and damage only)	0
Wildfire	acres burned (local data)	3 records, 2001 to 2012 (2 zone-level)		Wildfire, 2012-04-09, $10,000 property; $0 crops (2012 dollars); NWS zone PAZ070		Event records naming jurisdictions in the plan: Ridley Park borough (1 record). Zone-level records (2) apply countywide.
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet	none in data (snowfall: local data)	212 records, 1996 to 2026 (212 zone-level)		Winter Storm, 2010-02-09, $2,500,000 property; $0 crops (2010 dollars); NWS zone PAZ070		Countywide (zone-level records).

Where a hazard names more than 10 jurisdictions, the table lists the 10 with the most records; every one is in the Excel file, sheet "B1-c Extent".

In event narratives only (local data needed): wind chill, temperature, heat index, ice thickness, acres burned and snow depth; any physical measure of avalanche, debris flow, lightning and tsunami.

Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records from zones that no NWS zone-county file places in this county (mostly before 2020) are not counted here (the Methods page explains the zone matching).

Dollars are nominal (as reported), labeled with the year; not adjusted for inflation.

Supports FEMA checklist item B1-d: previous occurrences

Federal declarations for this county: 24 declarations covering 18 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

No county-level plan row in FEMA data, so there is no approval date to count from.

Federal disaster declarations for this county

Sources: 1, 2, 3

Declared	Incident began	FEMA number	Type	Title	Mapped hazard	County Public Assistancefederal share obligated, nominal dollars	Notes
2021-09-10	2021-08-31	DR-4618-PA	Major disaster	Remnants of Hurricane Ida	Hurricane	$30,763,530.18
2020-03-30	2020-01-20	DR-4506-PA	Major disaster	COVID-19 Pandemic	Non-natural, not counted	$27,082,698.58
2020-03-13	2020-01-20	EM-3441-PA	Emergency	COVID-19	Non-natural, not counted	no Public Assistance recorded	same incident as DR-4506
2014-02-06	2014-02-04	EM-3367-PA	Emergency	Severe Winter Storm	Ice Storm	no Public Assistance recorded
2012-10-29	2012-10-26	EM-3356-PA	Emergency	Hurricane Sandy	Hurricane	no Public Assistance recorded
2011-09-12	2011-09-03	DR-4030-PA	Major disaster	Tropical Storm Lee	Inland Flooding (primary); also designated: Hurricane	PA not declared for this county
2011-09-08	2011-09-03	EM-3340-PA	Emergency	Remnants of Tropical Storm Lee	Inland Flooding (primary); also designated: Hurricane	$50,879.01	same incident as DR-4030
2011-09-03	2011-08-26	DR-4025-PA	Major disaster	Hurricane Irene	Hurricane	$1,145,730.37
2011-08-29	2011-08-26	EM-3339-PA	Emergency	Hurricane Irene	Hurricane	no Public Assistance recorded	same incident as DR-4025
2010-04-16	2010-02-05	DR-1898-PA	Major disaster	Severe Winter Storms and Snowstorms	Winter Weather	$2,739,288.35
2005-09-10	2005-08-29	EM-3235-PA	Emergency	Hurricane Katrina	Hurricane: evacuation support, not a local hazard event; not counted	no Public Assistance recorded
2004-09-19	2004-09-17	DR-1557-PA	Major disaster	Tropical Depression Ivan	Hurricane	PA not declared for this county
2004-09-19	2004-09-08	DR-1555-PA	Major disaster	Severe Storms and Flooding Associated with Tropical Depression Frances	Hurricane; Inland Flooding: designated for Hazard Mitigation only (no Public or Individual Assistance for this county); not counted	PA not declared for this county
2004-08-06	2004-07-27	DR-1538-PA	Major disaster	Severe Storms and Flooding	Inland Flooding	PA not declared for this county
2003-03-14	2003-02-14	EM-3180-PA	Emergency	Snow	Winter Weather	$1,209,885.38
1999-09-18	1999-09-16	DR-1294-PA	Major disaster	Hurricane Floyd Major Disaster Declarations	Hurricane	$3,854,233.75
1996-01-21	1996-01-19	DR-1093-PA	Major disaster	Severe Storms and Flooding	Inland Flooding	PA not declared for this county
1996-01-13	1996-01-06	DR-1085-PA	Major disaster	Blizzard of 96	Winter Weather	no Public Assistance recorded
1994-03-10	1994-01-04	DR-1015-PA	Major disaster	Severe Winter Storms	Winter Weather	no Public Assistance recorded
1993-03-16	1993-03-13	EM-3105-PA	Emergency	Severe Snowfall & Winter Storm	Winter Weather	no Public Assistance recorded
1973-07-17	1973-07-17	DR-400-PA	Major disaster	Severe Storms & Flooding	Inland Flooding	no Public Assistance recorded
1972-06-23	1972-06-23	DR-340-PA	Major disaster	Tropical Storm Agnes	Inland Flooding (primary); also designated: Hurricane	no Public Assistance recorded
1971-09-18	1971-09-18	DR-312-PA	Major disaster	Floods	Inland Flooding	no Public Assistance recorded
1965-08-18	1965-08-18	DR-206-PA	Major disaster	Water Shortage	Drought	no Public Assistance recorded

County Public Assistance: applicants the FEMA record places in this county, including any state agencies FEMA files there; statewide rows are listed on the state page; federal share obligated, nominal dollars.

Statewide declarations

Source: 2

Declared	Incident began	FEMA number	Type	Title	Mapped hazard
2003-08-23	2003-07-21	DR-1485-PA	Major disaster	Severe Storms, Tornadoes, and Flooding	Inland Flooding; Tornado
1959-01-23	1959-01-23	DR-89-PA	Major disaster	Floods	Inland Flooding
1956-08-09	1956-08-09	DR-61-PA	Major disaster	Storm	Hazard not mapped (severe storm title names no single hazard); not counted
1956-05-21	1956-05-21	DR-58-PA	Major disaster	Severe Storm	Hazard not mapped (severe storm title names no single hazard); not counted
1956-03-15	1956-03-15	DR-51-PA	Major disaster	Flood	Inland Flooding
1955-08-20	1955-08-20	DR-40-PA	Major disaster	Floods & Rains	Inland Flooding

FEMA recorded these with designated area Statewide and no county, so they are listed on every county page in the state and not counted with county rows. Local data needed: whether each one affected this county.

Previous occurrences by hazard, with explicit no-event rows

Sources: 2, 6, 7

Hazard	Storm Events records, all years on file(years in the Period column)	Last 5 yearsrecords	Declared incidents, all yearsseparate disasters	Period	Statement
Avalanche	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Coastal Flooding	55	9	0	1996 to 2026-06-30
Cold Wave	30	1	0	1996 to 2026-06-30	Includes 1 Frost/Freeze record.
Drought	44	0	1	1996 to 2026-06-30
Earthquake	0	0	0		Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail	63	17	0	1955 to 2026-06-30
Heat Wave	103	12	0	1996 to 2026-06-30
Hurricane	3	0	7	1996 to 2026-06-30
Ice Storm	2	0	1	1996 to 2026-06-30
Inland Flooding	220	34	6	1996 to 2026-06-30
Landslide	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning	39	0	0	1996 to 2026-06-30
Strong Wind	477	53	0	1955 to 2026-06-30	Includes 38 High Wind and 101 Strong Wind records.
Tornado	5	0	0	1950 to 2026-06-30
Tsunami	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire	3	0	0	1996 to 2026-06-30
Winter Weather	212	23	5	1996 to 2026-06-30	Includes 4 Sleet records.

Notable Storm Events records

Sources: 1, 6, 7

Date	Event type	Magnitude or extent	Damagenominal dollars	Deaths, injuriesdirect only	Location	Flags	Why listed
2025-04-04	Thunderstorm Wind	91 kt (105 mph) estimated gust	damage not reported	0, 0	SWARTHMORE	within last 5 years	B1-c worst recorded: Thunderstorm Wind
2019-10-31	Tornado	EF2, 0.47 mi within this county, 250 yd wide	damage not reported	0, 2	GLEN MILLS		B1-c worst recorded: Tornado
2011-08-27	Tropical Storm		$500,000 property; $0 crops (zone total, 2011 dollars)	0, 0	NWS zone PAZ070 (DELAWARE), zone-level		B1-c worst recorded: Hurricane, Tropical Storm, Tropical Depression
2011-02-25	High Wind	55 kt (63 mph) measured gust	$100,000 property; $0 crops (zone total, 2011 dollars)	0, 0	NWS zone PAZ070 (DELAWARE), zone-level		B1-c worst recorded: High Wind and Strong Wind
2010-07-16	Excessive Heat		$0 property; $0 crops (zone total, 2010 dollars)	2, 0	NWS zone PAZ070 (DELAWARE), zone-level		deaths or injuries recorded
2010-02-09	Winter Storm		$2,500,000 property; $0 crops (zone total, 2010 dollars)	0, 0	NWS zone PAZ070 (DELAWARE), zone-level		B1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2008-06-07	Excessive Heat		$0 property; $0 crops (zone total, 2008 dollars)	1, 22	NWS zone PAZ070 (DELAWARE), zone-level		deaths or injuries recorded
2006-06-02	Lightning		$0 property; $0 crops (2006 dollars)	1, 0	BOOTHWYN		B1-c worst recorded: Lightning
2003-01-14	Cold/Wind Chill		damage not reported	0, 0	NWS zone PAZ070 (DELAWARE), zone-level		B1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
1999-09-16	Flash Flood		$15,000,000 property; crops not reported (1999 dollars)	1, 14	COUNTYWIDE		B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
1999-07-23	Heat		damage not reported	1, 0	NWS zone PAZ070 (DELAWARE), zone-level		B1-c worst recorded: Excessive Heat, Heat
1999-07-04	Heat		damage not reported	7, 0	NWS zone PAZ070 (DELAWARE), zone-level		deaths or injuries recorded

The full list is in the Excel file, sheet "B1-d Storm Events history" (1,256 rows).

Location is the place NOAA recorded, as written in its data; it need not be a jurisdiction in this plan.

Local data needed: state-declared emergencies, from your state emergency management agency (federal data do not include them).

FEMA's declaration data list no tribal or special-area declarations for this state.

Supports FEMA checklist item B1-e: probability of future events

Probability: FEMA annualized frequency and descriptor per hazard

Sources: 5, 6

Hazard	FEMA annualized frequency (modeled)unit per row	Unit	In plain terms	Descriptor	Descriptor basis	NRI events or days in its record period (hail, wind and tornado are area-weighted, so can be fractional)	NRI period	Location	Note
Avalanche	0.01	events per year	about 1 in 100 years	Possible	FEMA annualized frequency (modeled)	0	1994 to 2023 (30 years)	see B1-f	0.01 is NRI's minimum avalanche frequency for a county in an avalanche susceptibility zone; NRI records no avalanche here, so the descriptor reflects the floor, not local events.
Coastal Flooding	3.69	events per year at a location (modeled)	about 3.7 per year at a given location in the county	Highly likely	FEMA annualized frequency (modeled)	not shown	modeled	see B1-f	Descriptor from NRI: the rate at a location is 1 or more a year, so the county rate is at least that.
Cold Wave	0.791	event-days per year	about 0.791 days per year	Likely	Storm Events event-days in 13 of 30 years, 1996 to 2025 (43.3%)	15	2005-11-12 to 2024-11-12 (19 years)	countywide
Drought	5.71	event-days per year	about 5.71 days per year	Likely	Storm Events event-days in 10 of 30 years, 1996 to 2025 (33.3%)	168	2000 to 2025 (25.25 years; D3 and D4 only)	countywide
Earthquake	0.00162	annual probability at a location	chance a given location in the county has at least minor-damage shaking in a year: 0.162%			not shown	modeled	see B1-f	No descriptor (Storm Events does not record earthquakes).
Hail	2.47	events per year	about 2.47 per year	Highly likely	FEMA annualized frequency (modeled)	96.8 (modeled)	1986 to 2023 (38 years)	countywide
Heat Wave	11.1	event-days per year	about 11.1 days per year	Likely	Storm Events event-days in 24 of 30 years, 1996 to 2025 (80%)	125	2005-11-12 to 2024-11-12 (19 years)	countywide
Hurricane	0.092	events per year	about 1 in 11 years	Possible	FEMA annualized frequency (modeled)	16	1851 to 2024 (Atlantic)	see B1-f	NRI counts hurricane and tropical storm tracks passing within storm-force wind range; federal declarations are in B1-d.
Ice Storm	1.41	event-days per year	about 1.41 days per year	Possible	Storm Events event-days in 2 of 30 years, 1996 to 2025 (6.67%)	95	1946-12-31 to 2014-02-12 (67 years)	countywide
Inland Flooding	4.64	event-days per year	about 4.64 days per year	Highly likely	Storm Events event-days in 28 of 30 years, 1996 to 2025 (93.3%)	130	1996 to 2023 (28 years)	see B1-f
Landslide	0.16	events per year (modeled)	about 1 in 6 years	Likely	FEMA annualized frequency (modeled)	not shown	modeled	see B1-f
Lightning	36	days per year with a strike	about 36 days per year	Highly likely	FEMA annualized frequency (modeled)	not shown	1995 to 2023 (29 years; CONUS)	countywide
Strong Wind	6.94	events per year	about 6.94 per year	Highly likely	FEMA annualized frequency (modeled)	264	1986 to 2023 (38 years)	countywide
Tornado	0.097	events per year	about 1 in 10 years	Possible	FEMA annualized frequency (modeled)	not shown	1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)	see B1-f
Tsunami		annual probability at the most exposed location (used in place of a county value)			Storm Events records in 0 of 30 years, 1996 to 2025 (0%)	not shown	modeled	see B1-f	No descriptor: no Storm Events record 1996 to 2025
Wildfire	0.000086	annual probability at a location	chance a given location in the county burns in a year: 0.0086%	Likely	Storm Events records in 3 of 30 years, 1996 to 2025 (10%)	not shown	modeled	see B1-f
Winter Weather	10.5	event-days per year	about 10.5 days per year	Highly likely	Storm Events event-days in 29 of 30 years, 1996 to 2025 (96.7%)	199	2005-11-12 to 2024-11-12 (19 years)	countywide

FEMA annualized frequency (modeled) is the National Risk Index v1.20 (December 2025) estimate of how often a hazard affects this county in a year; it is not recorded events divided by years, and its unit differs by hazard (events, event-days, or days with a lightning strike per year). For earthquake, wildfire, coastal flooding and tsunami the value is the chance (or number of events) at a location in the county, not across the county, so no "1 in N years" is given and the descriptor comes from Storm Events where it has a record (none for earthquake). The Methods page gives each hazard's method, from FEMA's National Risk Index Technical Documentation v1.20.

Where NRI gives event-days, the descriptor comes from the share of years with a Storm Events record; NRI's source records more events, so the two differ.

Descriptor scale used in this packet (defined per unit)

Sources: 5, 6

Unit	Descriptor	Definition
events per year	Highly likely	1 or more per year
events per year	Likely	about once in 1 to 10 years
events per year	Possible	about once in 10 to 100 years
events per year	Unlikely	less than once in 100 years
annual probability	Likely	10% to under 100% chance in a given year
annual probability	Possible	1% to under 10% chance in a given year
annual probability	Unlikely	under 1% chance in a given year
event-days (share of years)	Highly likely	event-days recorded in 90% or more of years
event-days (share of years)	Likely	event-days recorded in 10% to under 90% of years
event-days (share of years)	Possible	event-days recorded in some years but under 10% of years
lightning strike-days	Highly likely	cloud-to-ground strikes on 1 or more days per year

Intensity bands: historical frequency (Storm Events)

Source: 6

Hazard	Band	Years	Eventscounty-coded records	Years in period	Events per yearevents / years
Hail	1.00-1.99 in	1996 to 2025	26	30	0.867
Hail	2.00 in+	1996 to 2025	0	30	0
Thunderstorm Wind (counted as NRI Strong Wind)	50-64 kt	1996 to 2025	258	30	8.6
Thunderstorm Wind (counted as NRI Strong Wind)	65 kt+	1996 to 2025	8	30	0.267
Thunderstorm Wind (counted as NRI Strong Wind)	unmeasured or below 50 kt	1996 to 2025	8	30	0.267
Tornado	EF0-1	1996 to 2025	1	30	0.0333
Tornado	EF2-3	1996 to 2025	1	30	0.0333
Tornado	EF4-5	1996 to 2025	0	30	0
Tornado	unrated (EFU)	1996 to 2025	0	30	0

The bands show how often events of each severity were recorded in this county, to profile how severe events have been (FEMA's probability item asks for the range of intensities).

Hail smaller than 1 inch is not counted: on 2010-01-05 the National Weather Service raised its severe-hail threshold from 3/4 inch to 1 inch, so smaller reports became less common after 2009 (NWS Service Change Notice 09-52). NRI hail frequency uses a 0.75 inch threshold.

Optional: future conditions. Not a required item in the 2025 FEMA Local Mitigation Planning Policy Guide; some states ask for it. The federal Climate Mapping for Resilience and Adaptation (CMRA) site gives county exposure to future climate conditions (https://resilience.climate.gov/).

Supports FEMA checklist item B1-f: hazards that vary across jurisdictions

Range of census tract risk within the county

Source: 5

Hazard	Tractsrated of all	NRI risk score, 0 to 100			Tracts by rating
Hazard	Tractsrated of all	Min	Median	Max	Tracts by rating
Avalanche	2 of 152	3.3	4.2	5.0	Very Low 2, Not Applicable 150
Coastal Flooding	22 of 152	70.1	89.3	96.5	Relatively High 2, Relatively Moderate 9, Relatively Low 9, Very Low 2, No Rating 130
Cold Wave	152 of 152	15.6	48.5	76.0	Relatively Moderate 80, Relatively Low 69, Very Low 3
Drought	19 of 152	69.1	84.5	93.2	Relatively Moderate 1, Relatively Low 12, Very Low 6, No Rating 133
Earthquake	152 of 152	23.7	69.6	84.0	Relatively Moderate 14, Relatively Low 135, Very Low 3
Hail	152 of 152	1.1	4.2	35.7	Very Low 152
Heat Wave	152 of 152	1.3	70.4	92.2	Relatively High 20, Relatively Moderate 109, Relatively Low 20, Very Low 3
Hurricane	152 of 152	47.0	61.7	79.1	Relatively Moderate 1, Relatively Low 149, Very Low 2
Ice Storm	152 of 152	4.0	45.5	74.6	Relatively Moderate 5, Relatively Low 126, Very Low 21
Inland Flooding	152 of 152	0.6	30.8	89.8	Relatively High 5, Relatively Moderate 40, Relatively Low 67, Very Low 40
Landslide	152 of 152	10.0	33.8	87.4	Relatively Low 9, Very Low 143
Lightning	152 of 152	0.5	50.8	85.1	Relatively High 3, Relatively Moderate 78, Relatively Low 68, Very Low 3
Strong Wind	152 of 152	12.2	65.4	88.8	Relatively High 10, Relatively Moderate 116, Relatively Low 24, Very Low 2
Tornado	152 of 152	10.1	46.3	68.3	Relatively Moderate 37, Relatively Low 113, Very Low 2
Tsunami	0 of 152				Insufficient Data 152
Wildfire	92 of 152	18.5	32.1	69.3	Relatively Low 2, Very Low 90, No Rating 60
Winter Weather	152 of 152	24.7	84.9	97.0	Very High 4, Relatively High 117, Relatively Moderate 29, Relatively Low 2

Drought: Agriculture is all of NRI's expected annual loss for this hazard in the county, so the tract range mostly reflects where crop and livestock value is.

Rated tracts only: No Rating (score 0.0), Not Applicable and Insufficient Data tracts are counted but not used for the minimum, median and maximum.

The score ranks a tract against all U.S. tracts (100 = highest). The rating is FEMA's category for the tract's risk value, computed differently, so the two can disagree.

Frequency data for cold wave, drought, hail, heat wave, ice storm, lightning, strong wind and winter weather are county-wide or coarse (49 km grid or NWS zone), the same for every jurisdiction; the tract range mostly reflects where buildings and people are (crop and livestock value where a line above names agriculture).

Each jurisdiction (starting figures from federal data)

Sources: 1, 3, 4, 6

Jurisdiction	Type	Plan status	Repetitive lossFMA RL and SRL (44 CFR 77.2); repeat-flood, any definition	Public Assistance to this jurisdictionFEMA records matched by applicant name; federal share obligated, nominal dollars	Event records naming this placeall years; since its plan	Notes
Aldan borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$39,850.79	4 total; no approved plan
Brookhaven borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 2; any 9	$101,656.87	16 total; 1 since its plan	Includes $24,293.77 for declarations not counted as hazard incidents (DR-4506-PA).
Chester city	City	Approved, expires 2028-02-26	FMA RL 0, SRL 10; any 29	$487,072.36	23 total; 6 since its plan
Chester Heights borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 0	$11,304.17	7 total; 2 since its plan
Clifton Heights borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 1; any 1	$69,998.56	2 total; no approved plan
Collingdale borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 1; any 6	$43,566.23	3 total; no approved plan
Colwyn borough	Organized Borough	No approved plan on record	FMA RL 3, SRL 5; any 15	$267,127.96	0 total; no approved plan
Darby borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 1, SRL 19; any 38	$469,157.81	10 total; 0 since its plan
East Lansdowne borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$4,467.26	11 total; no approved plan
Eddystone borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 1	$101,416.60	10 total; no approved plan
Folcroft borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$31,130.09	11 total; no approved plan
Glenolden borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 1	$79,248.93	7 total; no approved plan
Lansdowne borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 1	$234,127.94	4 total; 0 since its plan
Marcus Hook borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 0	$36,649.69	14 total; 1 since its plan
Media borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 1	$144,821.24	20 total; 6 since its plan	Includes $4,532.51 for declarations not counted as hazard incidents (DR-4506-PA).
Millbourne borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$11,314.28	0 total; no approved plan
Morton borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 1	$33,379.22	5 total; no approved plan
Norwood borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$34,304.28	3 total; no approved plan
Parkside borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$1,419.92	2 total; no approved plan
Prospect Park borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 0	$47,478.79	1 total; 0 since its plan
Ridley Park borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$119,025.55	11 total; no approved plan	Includes $14,316.66 for declarations not counted as hazard incidents (DR-4506-PA).
Rose Valley borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$35,358.85	0 total; no approved plan
Rutledge borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$774.47	11 total; no approved plan
Sharon Hill borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 0	$27,857.46	6 total; no approved plan
Swarthmore borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 2	$22,922.33	4 total; no approved plan
Trainer borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 2; any 2	$31,832.79	12 total; no approved plan
Upland borough	Organized Borough	Approved, expires 2028-02-26	FMA RL 3, SRL 11; any 33	$71,489.43	2 total; 0 since its plan
Yeadon borough	Organized Borough	No approved plan on record	FMA RL 0, SRL 0; any 2	$88,381.62	2 total; no approved plan	Includes $34,889.31 for declarations not counted as hazard incidents (DR-4506-PA).
Aston township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 5	$203,614.15	0 total; 0 since its plan	Includes $8,687.95 for declarations not counted as hazard incidents (DR-4506-PA).
Bethel township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 0	$17,104.34	0 total; 0 since its plan
Chadds Ford township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 3; any 12	$103,287.98	38 total; 6 since its plan
Chester township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	FMA RL 1, SRL 8; any 16	$142,258.74	23 total; no approved plan
Concord township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 1; any 4	$116,347.61	0 total; 0 since its plan	Includes $23,094.80 for declarations not counted as hazard incidents (DR-4506-PA).
Darby township	Township	No approved plan on record	FMA RL 0, SRL 0; any 2	$33,354.54	10 total; no approved plan
Edgmont township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	0 total; 0 since its plan
Haverford township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	FMA RL 0, SRL 1; any 17	$366,828.24	5 total; no approved plan
Lower Chichester township	Township	Approved, expires 2028-02-26	FMA RL 1, SRL 0; any 1	$24,434.76	0 total; 0 since its plan
Marple township	Township	Approved, expires 2028-02-26	FMA RL 1, SRL 2; any 5	$121,902.08	0 total; 0 since its plan
Middletown township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 2; any 4	$67,411.67	0 total; 0 since its plan
Nether Providence township	Township	No approved plan on record	FMA RL 0, SRL 2; any 2	$135,522.50	0 total; no approved plan	Includes $7,211.85 for declarations not counted as hazard incidents (DR-4506-PA).
Newtown township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 2	$79,739.33	0 total; 0 since its plan	Includes $7,128.80 for declarations not counted as hazard incidents (DR-4506-PA).
Radnor township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 19	$477,887.64	12 total; 2 since its plan	Includes $104,182.97 for declarations not counted as hazard incidents (DR-4506-PA).
Ridley township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 1; any 16	$217,588.49	0 total; 0 since its plan	Includes $67,630.50 for declarations not counted as hazard incidents (DR-4506-PA).
Springfield township	Township	Approved, expires 2028-02-26	FMA RL 1, SRL 10; any 21	$217,737.47	14 total; 1 since its plan	Includes $27,729.38 for declarations not counted as hazard incidents (DR-4506-PA).
Thornbury township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 0; any 1	$81,625.25	0 total; 0 since its plan
Tinicum township	Township	No approved plan on record	FMA RL 0, SRL 1; any 4	$113,838.05	0 total; no approved plan
Upper Chichester township	Township	Approved, expires 2028-02-26	FMA RL 0, SRL 1; any 4	$86,094.49	0 total; 0 since its plan
Upper Darby township	Township	No approved plan on record	FMA RL 1, SRL 7; any 57	$704,646.04	6 total; no approved plan	Includes $80,933.18 for declarations not counted as hazard incidents (DR-4506-PA).
Upper Providence township	Township	Plan 108724 approved 2023-02-27, pending adoption here; not yet eligible	FMA RL 0, SRL 0; any 0	$36,252.41	0 total; no approved plan

Repetitive-loss counts are for whole NFIP communities, which can extend beyond this county (see the note in B2-c).

School districts and special districts get a plan clock row only.

County Public Assistance in B1-d also includes applicants filed under the county that are not jurisdictions in this plan (for example state agencies, special districts and nonprofits), so the jurisdiction rows add up to less.

Supports FEMA checklist items B2-a and B2-b: vulnerability and potential impacts

Local data needed

The table below gives county-level starting figures; the plan describes impacts for each jurisdiction and its own assets.

No county-level plan row in FEMA data, so there is no approval date to count from.

Critical facilities and lifelines per hazard
A problem statement per jurisdiction per hazard
Changes in development in hazard-prone areas since the last approval, or a statement of none (E1-a)
Future assets

County-level starter: exposure, expected annual loss and damage since the plan

Sources: 1, 2, 3, 5, 6, 7

Hazard	Building exposuremodeled dollars	Agriculture exposuremodeled dollars	Population exposedpeople	EAL buildingsmodeled dollars per year	EAL agriculturemodeled dollars per year	Cost of expected deaths and injuriesFEMA's dollar value per year, not property damage	EAL as % of exposurebuildings; agriculture where noted	Note
Avalanche	$0	n/a	under 1	$0	n/a	$11		building exposure is 0 in NRI
Coastal Flooding	$5,472,514,967	n/a	17,538	$723,470	n/a	$6,696	0.0132%
Cold Wave	$133,367,188,695	$12,224,902	576,366	$1,597	$4	$8,510,938	under 0.0001%
Drought	n/a	$11,154,679	n/a	n/a	$208,692	n/a	1.87% (agriculture)	NRI has no building exposure for this hazard; agriculture shown
Earthquake	$226,800,744,517	n/a	576,830	$9,147,333	n/a	$4,116,397	0.00403%
Hail	$133,367,188,695	$12,224,902	576,366	$30,309	$13,347	$2,127	under 0.0001%
Heat Wave	$133,367,188,695	$12,224,902	576,366	$8	$157	$12,832,305	under 0.0001%
Hurricane	$133,336,275,288	$12,224,902	576,142	$5,627,996	$46,911	$180,145	0.00422%
Ice Storm	$133,192,011,086	n/a	575,319	$425,926	n/a	$324,042	0.00032%
Inland Flooding	$133,274,683,734	$88,728	10,412	$72,491,995	$3,352	$1,373,549	n/a (see note)	NRI counts the full building value of any census block with some flood loss; this is not the value of buildings in the floodplain. Use local FIRM overlays for B2-a/B2-b.
Landslide	$3,237,915,567	n/a	11,834	$2,624	n/a	$135	under 0.0001%
Lightning	$133,367,188,695	n/a	576,366	$117,552	n/a	$2,015,701	under 0.0001%
Strong Wind	$133,367,188,695	$12,224,902	576,366	$1,824,232	$2,502	$3,358,606	0.00137%
Tornado	$133,367,188,695	$12,224,902	576,366	$4,941,096	$140	$4,463,139	0.0037%
Tsunami	n/a	n/a	n/a	n/a	n/a	n/a		NRI publishes no building exposure for this county
Wildfire	$2,294,564,376	$1,403,643	19,768	$10,313	$1	$2,697	0.000449%
Winter Weather	$133,367,188,695	$12,224,902	576,366	$608,737	$4	$1,531,182	0.000456%

Totals since the plan: not available. No county-level plan row in FEMA data, so there is no approval date to count from.

FEMA does not split Public Assistance by hazard. A declaration mapped to several hazards is listed under each of them with its full amount, so the per-hazard column does not add up to the total; the unit total counts each declaration once.

NRI computes earthquake exposure on its own basis, so it exceeds the county building value in B2-a.

Supports FEMA checklist item B2-a: vulnerability (county context)

County context

Source: 5

Measure	Value
Population	576,366
Building value (total, not at risk)	$133,367,188,695
Agriculture value (total, not at risk)	$12,224,902
NRI risk rating (all hazards)	Relatively Moderate
Expected annual loss, buildings and agriculture, all hazards	$96,228,298
Expected annual loss, population equivalence, all hazards (NRI values each statistical life at $13.7M; a modeled value of expected deaths and injuries, not property damage)	$38,717,670
Social vulnerability rating	Relatively Low
Community resilience rating	Very High
NRI version	December 2025

FEMA's all-hazard expected annual loss adds buildings, agriculture and population equivalence; this table gives the property part and the population-equivalence part as separate rows.

Social vulnerability: higher means people are more likely to be harmed and slower to recover. Community resilience: lower means the community is less able to recover. High social vulnerability and low resilience both raise the NRI risk rating.

Supports FEMA checklist item B2-c: repetitive loss properties

Repetitive loss in this county, both definitions

Sources: 1, 4

Definition	Properties	Severe repetitive loss	Properties
Repetitive loss, FMA definition (44 CFR 77.2)	12	Severe repetitive loss, FMA definition (44 CFR 77.2)	90
Repetitive loss, NFIP insurance definition	335	Severe repetitive loss, NFIP insurance definition	89

The state NFIP coordinator's list, the source FEMA's Handbook names, often uses the NFIP insurance definition (second row).

Repeat-flood properties: county and state-level rows

Sources: 1, 4

Scope	RL, FMAproperties	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Mitigatedproperties	Currently insuredproperties
County total	12	90	335	89	337	1	117
of which: Chadds Ford township	0	3	12	3	12	0	7
of which: Brookhaven borough	0	2	9	2	9	0	4
of which: Chester city	0	10	29	10	29	0	2
of which: Chester township	1	8	16	8	16	0	4
of which: Clifton Heights borough	0	1	1	1	1	0	0
of which: Collingdale borough	0	1	6	1	6	0	1
of which: Colwyn borough	3	5	15	6	15	0	9
of which: Concord township	0	1	4	1	4	0	1
of which: Darby borough	1	19	37	17	38	0	12
of which: Eddystone borough	0	0	1	0	1	0	0
of which: Glenolden borough	0	0	1	0	1	0	0
of which: Haverford township	0	1	17	1	17	0	10
of which: Lansdowne borough	0	0	1	0	1	0	0
of which: Marple township	1	2	5	2	5	0	3
of which: Media borough	0	0	1	0	1	0	0
of which: Middletown township	0	2	4	2	4	0	1
of which: Morton borough	0	0	1	0	1	0	0
of which: Nether Providence township	0	2	2	2	2	0	0
of which: Radnor township	0	0	19	0	19	0	10
of which: Ridley township	0	1	16	1	16	0	6
of which: Springfield township	1	10	21	10	21	0	13
of which: Swarthmore borough	0	0	2	0	2	0	2
of which: Trainer borough	0	2	2	2	2	0	0
of which: Upland borough	3	11	33	13	33	0	5
of which: Upper Chichester township	0	1	4	1	4	0	3
of which: Upper Darby township	1	7	57	6	57	0	18
of which: Yeadon borough	0	0	2	0	2	0	0
of which: Newtown township	0	0	2	0	2	0	2
of which: Aston township	0	0	5	0	5	0	2
of which: Darby township	0	0	2	0	2	0	0
of which: Lower Chichester township	1	0	1	0	1	0	1
of which: Tinicum township	0	1	3	0	4	1	1
of which: Thornbury township	0	0	1	0	1	0	0
of which: Unknown (community ID Unknown in FEMA data)	0	0	3	0	3	0	0
Statewide, no county in FEMA's file	0	0	1	0	1	0	0

The statewide row counts properties FEMA's file gives with no county in this state; they are listed for reference and are not in this county's counts.

Repeat-flood properties by jurisdiction in the plan (NFIP community)

Sources: 1, 4

Jurisdiction	NFIP community ID	RL, FMAproperties	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Mitigatedproperties	Currently insuredproperties
Aldan borough	420401	0	0	0	0	0	0	0
Brookhaven borough	420403	0	2	9	2	9	0	4
Chester city	420404	0	10	29	10	29	0	2
Chester Heights borough	420406	0	0	0	0	0	0	0
Clifton Heights borough	420407	0	1	1	1	1	0	0
Collingdale borough	420408	0	1	6	1	6	0	1
Colwyn borough	420409	3	5	15	6	15	0	9
Darby borough	420411	1	19	37	17	38	0	12
East Lansdowne borough	420412	0	0	0	0	0	0	0
Eddystone borough	420413	0	0	1	0	1	0	0
Folcroft borough	420415	0	0	0	0	0	0	0
Glenolden borough	420416	0	0	1	0	1	0	0
Lansdowne borough	420418	0	0	1	0	1	0	0
Marcus Hook borough	420419	0	0	0	0	0	0	0
Media borough	420421	0	0	1	0	1	0	0
Millbourne borough	422408	0	0	0	0	0	0	0
Morton borough	420423	0	0	1	0	1	0	0
Norwood borough	420425	0	0	0	0	0	0	0
Parkside borough	420426	0	0	0	0	0	0	0
Prospect Park borough	420427	0	0	0	0	0	0	0
Ridley Park borough	420430	0	0	0	0	0	0	0
Rose Valley borough	420431	0	0	0	0	0	0	0
Rutledge borough	420432	0	0	0	0	0	0	0
Sharon Hill borough	420433	0	0	0	0	0	0	0
Swarthmore borough	420435	0	0	2	0	2	0	2
Trainer borough	420437	0	2	2	2	2	0	0
Upland borough	420438	3	11	33	13	33	0	5
Yeadon borough	420442	0	0	2	0	2	0	0
Aston township	421602	0	0	5	0	5	0	2
Bethel township	421606	0	0	0	0	0	0	0
Chadds Ford township	420402	0	3	12	3	12	0	7
Chester township	420405	1	8	16	8	16	0	4
Concord township	420410	0	1	4	1	4	0	1
Darby township	421603	0	0	2	0	2	0	0
Edgmont township	420414	0	0	0	0	0	0	0
Haverford township	420417	0	1	17	1	17	0	10
Lower Chichester township	421604	1	0	1	0	1	0	1
Marple township	420420	1	2	5	2	5	0	3
Middletown township	420422	0	2	4	2	4	0	1
Nether Providence township	420424	0	2	2	2	2	0	0
Newtown township	420991	0	0	2	0	2	0	2
Radnor township	420428	0	0	19	0	19	0	10
Ridley township	420429	0	1	16	1	16	0	6
Springfield township	420434	1	10	21	10	21	0	13
Thornbury township	425390	0	0	1	0	1	0	0
Tinicum township	421605	0	1	3	0	4	1	1
Upper Chichester township	420439	0	1	4	1	4	0	3
Upper Darby township	420440	1	7	57	6	57	0	18
Upper Providence township	420441	0	0	0	0	0	0	0

Counts by occupancy group for each jurisdiction are in the Excel file, sheet "B2-c Jurisdictions".

Jurisdiction rows are whole NFIP communities and need not add up to the county total: a community that extends into another county is counted in full on each jurisdiction row, while the county table counts only its part in this county.

County repeat-flood properties by occupancy group

Sources: 1, 4

Occupancy group	RL, FMAproperties	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Mitigatedproperties	Currently insuredproperties
single-family residential	4	49	227	46	229	1	82
2 to 4 unit residential	0	7	14	7	14	0	3
other residential	1	3	8	3	8	0	5
non-residential	7	31	86	33	86	0	27
not reported	0	0	0	0	0	0	0

FEMA's occupancy groups have no institutional class; institutional properties are counted in non-residential or other residential in the table by occupancy group.

FMA RL and FMA SRL are the Flood Mitigation Assistance definitions (44 CFR 77.2), the ones the FEMA Local Mitigation Planning Policy Guide cites. NFIP repetitive loss (the FEMA insurance definition) is 2 or more claims over $1,000 in 10 years, and a property can leave that group once it is mitigated. Also shown: NFIP severe repetitive loss, any category, mitigated and currently insured. The Methods page gives the OpenFEMA field details.

Counts are aggregates of FEMA's public NFIP Multiple Loss Properties file (FEMA's data date 2026-08-02; file version 2026-08-04). No property is identified. County assignment is FEMA's geocode.

In this county 0 properties are FMA repetitive loss but not NFIP repetitive loss, and 323 properties are NFIP repetitive loss but not FMA repetitive loss.

Exact counts; no count suppression.

Sources

Tables cite these sources by number. The full list, for the plan's bibliography (FEMA review item A4-a):

FEMA, OpenFEMA HazardMitigationPlanStatuses v1, version 2026-09-29T134039Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/HazardMitigationPlanStatuses (API)
FEMA, OpenFEMA DisasterDeclarationsSummaries v2, version 2026-09-29T162832Z, pulled 2026-09-30, https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries (API)
FEMA, OpenFEMA PublicAssistanceFundedProjectsSummaries v1, version 2026-09-29T150754Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/PublicAssistanceFundedProjectsSummaries (API)
FEMA, OpenFEMA NfipMultipleLossProperties v1, version 2026-08-04T164045Z, pulled 2026-09-30, https://www.fema.gov/api/open/v1/NfipMultipleLossProperties (API)
FEMA, FEMA National Risk Index 1.20.0 (December 2025), county and census tract tables, version 1.20.0, pulled 2026-09-30, https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_Counties.zip (download, 25 MB), https://www.fema.gov/about/reports-and-data/openfema/nri/v120/NRI_Table_CensusTracts.zip (download, 635 MB)
NOAA NCEI, NOAA NCEI Storm Events Database, details files (csvfiles v1.0), version c20260918, pulled 2026-09-30, https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/
NOAA National Weather Service, NWS county-public forecast zones correlation file, version bp03mr20 to bp16ap26 (11 files; newest bp16ap26), pulled 2026-09-30, https://www.weather.gov/gis/ZoneCounty
U.S. Census Bureau, Census 2024 Gazetteer, 2020 place by county, CT county-to-cousub crosswalk, version 2024-gazetteer, pulled 2026-09-30, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_counties_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_cousubs_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_place_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_unsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_elsd_national.zip, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/2024_Gaz_scsd_national.zip, https://www2.census.gov/geo/docs/reference/codes2020/national_place_by_county2020.txt, https://www2.census.gov/geo/docs/reference/ct_change/ct_cou_to_cousub_crosswalk.xlsx (used to match place names and codes; no table prints its values)

What this packet is and what the plan adds

This packet is the federal data for the plan's risk assessment (the summary on page 1 says how it is organized); the plan and FEMA's review decide whether each item is met.

The plan adds what only the community has: local data on assets, critical facilities, development and each jurisdiction's impacts; local hazard history, including state-declared emergencies; the mitigation strategy; and adoption.

How the federal data are built: National Risk Index values are FEMA's model, not counts of events. Storm Events is more complete from 1996; zone-level records are placed by forecast zone, not by location in the county. Public Assistance for a jurisdiction is matched by applicant name. The Methods page gives every rule and the known edge cases.

OpenFEMA disclaimer

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

Reuse, citation and corrections

Reuse and citation: Hazard Plain text and tables are licensed under Creative Commons Attribution 4.0 International (CC BY 4.0, https://creativecommons.org/licenses/by/4.0/); credit Hazard Plain and the release. The underlying federal data are public domain; OpenFEMA data are also subject to the OpenFEMA terms and conditions.

Cite this: Hazard Plain (2026). Delaware County, PA: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 42045). Automated baseline. https://hazardplain.org/pa/42045/ Built from FEMA OpenFEMA, the FEMA National Risk Index and NOAA NCEI Storm Events; source versions in the packet's Sources list.

Corrections: to report an error, name the packet, the table and what your records show. Contact: [email protected]