Grundy County, IL: risk-assessment baseline packet, release 2026-10

Summary

Plan status as of 2026-09-30: Expired on 2026-04-13. Plan: Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007), approved 2021-04-14.

Since the plan was approved on 2021-04-14: no new hazard declaration and 92 NOAA Storm Events records; details under "What changed since your last plan".

Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($22,176,238 a year), Cold Wave ($19,929,274) and Tornado ($4,726,398).

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; 17063 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

Status:: Expired on 2026-04-13
Plan:: Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)
Approved:: 2021-04-14
Days since expiry:: 170
Update underway:: none recorded in FEMA's plan tracker

Until a new plan is approved, FEMA mitigation project grants (HMGP, FMA) need a FEMA exception (44 CFR 201.6(a)(3)).

What changed since your last plan (approved 2021-04-14)

New federal declarations:: none
Storm Events records since approval:: 92 records (data through 2026-06-30)
Repetitive loss now:: FMA RL 6, SRL 6 (44 CFR 77.2); any definition: 46
Repeat-flood change:: this release sets the baseline count.

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

Plan status for every jurisdiction listed in this county: 14 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
Grundy County	County	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Braidwood city	City	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170	FEMA tracker shows a plan approvable pending adoption	Not yet eligible: adopt the approved plan.
Carbon Hill village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170		this jurisdiction approved 2021-04-26
Channahon village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170	FEMA tracker shows a plan approvable pending adoption	Not yet eligible: adopt the approved plan.
Coal City village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Diamond village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Dwight village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Kinsman village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Mazon village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Morris city	City	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Seneca village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
South Wilmington village	Village	Expired on 2026-04-13	Grundy County 2021 Hazard Mitigation Plan (FEMA plan 106007)	2021-04-14	2026-04-13	-170
Lisbon Community Consolidated School District 90	School/School District	Approved, expires 2029-05-01	Kendall County 2024 Hazard Mitigation Plan (FEMA plan 109742)	2024-05-02	2029-05-01	944		this jurisdiction approved 2024-10-17
Newark Community High School District 18	School/School District	Approved, expires 2029-05-01	Kendall County 2024 Hazard Mitigation Plan (FEMA plan 109742)	2024-05-02	2029-05-01	944

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 Low	Relatively Moderate	$21,998,384	$125,702	$52,152	$22,176,238	43
2	Cold Wave	Relatively High	Very High	$19	$1,320	$19,927,936	$19,929,274	22	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).
3	Tornado	Relatively Moderate	Relatively Moderate	$2,352,535	$1,819	$2,372,044	$4,726,398	14
4	Strong Wind	Relatively Moderate	Relatively Moderate	$999,033	$19,489	$534,782	$1,553,304	182	Includes 15 High Wind and 4 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
5	Earthquake	Very Low	Relatively Low	$619,533	n/a	$134,983	$754,517		Storm Events does not record earthquakes.
6	Heat Wave	Relatively Low	Relatively Low	$5,537	$2	$586,577	$592,117	12
7	Lightning	Very Low	Relatively Low	$17,468	n/a	$104,984	$122,453	9
8	Drought	Relatively Low	Relatively Low	n/a	$101,326	n/a	$101,326	13
9	Hail	Very Low	Very Low	$68,601	$2,667	$4,960	$76,227	60
10	Winter Weather	Relatively Low	Relatively Low	$8,619	$810	$37,653	$47,083	65	Includes 1 Sleet record (outside NRI's Winter Weather definition).
11	Ice Storm	Very Low	Relatively Low	$27,124	n/a	$18,407	$45,531	3
12	Wildfire	Very Low	Very Low	$9,957	$5	$587	$10,549	1
13	Hurricane	Very Low	Very Low	$965	$2,319	under $1	$3,285	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
14	Landslide	Very Low	Very Low	$109	n/a	$708	$817	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 records (Storm Events records this hazard only in part).

Not applicable to this county per NRI, with no federal declaration and no Storm Events record since 1996: avalanche, coastal flooding, tsunami and 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.

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
Earthquake	tract 4 (Relatively Low, 73.8); tract 2 (Relatively Low, 72.6); tract 1.02 (Relatively Low, 67.4)
Hurricane	tract 6 (Very Low, 34.3); tract 2 (Very Low, 29.8); tract 5 (Very Low, 26.4)
Landslide	tract 7 (Relatively Low, 86.0); tract 2 (Relatively Low, 83.8); tract 5 (Relatively Low, 82.7)
Tornado	tract 4 (Very High, 97.4); tract 2 (Very High, 96.3); tract 7 (Very High, 95.7)
Wildfire	tract 7 (Relatively Low, 79.1); tract 9 (Very Low, 68.5); tract 1.03 (Very Low, 66.3)

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 4 is Census Tract 4). 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
Cold/Wind Chill, Extreme Cold/Wind Chill	wind chill	21 records, 1996 to 2026 (21 zone-level)	1 day to 5 days (median 2 days); 20 with a recorded value	5 consecutive days, 2010-01-01 to 2010-01-05, 1 direct death, zone-level		Countywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)	crop damage	1 record, 2004 (1 zone-level)		No crop damage reported in 1 record.		Countywide (zone-level records).
Drought	U.S. Drought Monitor scale (D0 to D4)	13 records, 2005 to 2025 (13 zone-level)	4 days to 240 days (median 20.5 days); 4 with a recorded value	240 days (about 7.9 months), 2005-06-15 to 2006-02-09, a run of 9 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)	75 records, 1980 to 2024	0.75 in to 2.75 in (median 1 in); 74 with a recorded value	2.75 in hail, 2015-06-10	Hail, 1993-08-01, $500,000 property; $500,000 crops (1993 dollars)	Event records naming jurisdictions in the plan: Morris city (23 records), Coal City village (12 records), Mazon village (8 records), Kinsman village (4 records), Channahon village (1 record), Seneca village (1 record), South Wilmington village (1 record).
Excessive Heat, Heat	heat index (in event narratives)	12 records, 2009 to 2026 (12 zone-level)	1 day to 4 days (median 2 days); 11 with a recorded value	4 consecutive days, 2009-06-22 to 2009-06-25, 1 direct death, zone-level		Countywide (zone-level records).
Hurricane, Tropical Storm, Tropical Depression	Saffir-Simpson	0					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)	3 records, 2007 to 2021 (3 zone-level)		No damage reported in 3 records.		Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flood	damage and flood days (flood depth: FIRM)	43 records, 1996 to 2026 (3 zone-level)		Flash Flood, 1996-07-17, $1,000,000 property; $16,000,000 crops (1996 dollars)		Event records naming jurisdictions in the plan: Kinsman village (9 records), Morris city (8 records), Carbon Hill village (2 records), Mazon village (2 records), Channahon village (1 record), Coal City village (1 record), Diamond village (1 record). Zone-level records (3) 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)	9 records, 2000 to 2013		Lightning, 2009-07-24, $100,000 property; $0 crops (2009 dollars)		Event records naming jurisdictions in the plan: Morris city (3 records), Mazon village (1 record), South Wilmington village (1 record).	Storm Events lists lightning with damage or casualties.
High Wind and Strong Wind (outside NRI's Strong Wind definition)	wind speed (kt and mph)	19 records, 1996 to 2026 (19 zone-level)	43 kt (49 mph) to 59 kt (68 mph) (median 50 kt (58 mph)); 18 with a recorded value	59 kt (68 mph), measurement type not recorded, High Wind, 1997-04-06; NWS zone ILZ021	High Wind, 2010-10-26, $50,000 property; $0 crops (zone total, 2010 dollars)	Countywide (zone-level records).
Thunderstorm Wind	wind speed (kt and mph)	197 records, 1960 to 2026	50 kt (58 mph) to 78 kt (90 mph) (median 56 kt (64 mph)); 168 with a recorded value	78 kt (90 mph) estimated gust, Thunderstorm Wind, 2014-06-30	Thunderstorm Wind, 2003-07-07, $2,500,000 property; crops not reported (2003 dollars)	Event records naming jurisdictions in the plan: Morris city (53 records), Coal City village (23 records), Mazon village (20 records), Carbon Hill village (5 records), Channahon village (4 records), Diamond village (3 records), South Wilmington village (2 records), Dwight village (1 record), Kinsman village (1 record), Seneca village (1 record).
Tornado	Enhanced Fujita (Fujita before Feb 2007)	23 records, 1958 to 2024	F/EF0 to F/EF3 (median F/EF1); 22 with a recorded value	EF3 tornado, 2015-06-22, 7.7 mi within this county, 1,320 yd wide, $25,000,000 property; $0 crops (2015 dollars), 7 direct injuries		Event records naming jurisdictions in the plan: Diamond village (2 records), Channahon village (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).
Wildfire	acres burned (local data)	1 record, 2003		No damage reported in 1 record.		Event records naming jurisdictions in the plan: Morris city (1 record).
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet	none in data (snowfall: local data)	65 records, 1997 to 2026 (65 zone-level)		Winter Weather, 2015-02-14, $300,000 property; $0 crops (2015 dollars); NWS zone ILZ021		Countywide (zone-level records).

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

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: 15 declarations covering 12 separate hazard incidents counted in this packet (declarations for the same incident count once; non-natural and evacuation-only declarations are not counted).

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
2020-03-26	2020-01-20	DR-4489-IL	Major disaster	COVID-19 Pandemic	Non-natural, not counted	$1,057,326.69
2020-03-13	2020-01-20	EM-3435-IL	Emergency	COVID-19	Non-natural, not counted	no Public Assistance recorded	same incident as DR-4489
2013-11-26	2013-11-17	DR-4157-IL	Major disaster	Severe Storms, Straight-Line Winds, and Tornadoes	Tornado (primary); also designated: Strong Wind	PA not declared for this county
2013-05-10	2013-04-16	DR-4116-IL	Major disaster	Severe Storms, Straight-Line Winds, and Flooding	Inland Flooding (primary); also designated: Strong Wind	$111,237.38
2011-03-17	2011-01-31	DR-1960-IL	Major disaster	Severe Winter Storm and Snowstorm	Winter Weather	$178,137.97
2008-10-03	2008-09-13	DR-1800-IL	Major disaster	Severe Storms and Flooding	Inland Flooding	$105,274.58
2007-09-25	2007-08-20	DR-1729-IL	Major disaster	Severe Storms and Flooding	Inland Flooding	PA not declared for this county
2005-09-07	2005-08-29	EM-3230-IL	Emergency	Hurricane Katrina Evacuation	Hurricane: evacuation support, not a local hazard event; not counted	no Public Assistance recorded
2001-01-17	2000-12-11	EM-3161-IL	Emergency	Illinois Winter Snow Storms	Winter Weather	$88,077.89
1999-01-08	1999-01-01	EM-3134-IL	Emergency	Il-Winter Storm 1/1/99	Winter Weather	$63,266.92
1996-07-25	1996-07-17	DR-1129-IL	Major disaster	Severe Storms and Flooding	Inland Flooding	no Public Assistance recorded
1985-03-29	1985-02-23	DR-735-IL	Major disaster	Severe Storms & Flooding	Inland Flooding	PA not declared for this county
1979-01-16	1979-01-16	EM-3068-IL	Emergency	Blizzards & Snowstorms	Winter Weather	no Public Assistance recorded
1974-06-10	1974-06-10	DR-438-IL	Major disaster	Severe Storms & Flooding	Inland Flooding	no Public Assistance recorded
1972-09-04	1972-09-04	DR-351-IL	Major disaster	Severe Storms & Flooding	Inland Flooding	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
1961-05-27	1961-05-27	DR-115-IL	Major disaster	Floods & Tornadoes	Inland Flooding (primary); also designated: Tornado
1957-06-22	1957-06-22	DR-78-IL	Major disaster	Floods	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.

Public Assistance not placed in any Illinois county: 1 row, $797,909.42; listed on the Illinois state page.

Source: 3

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)	Since plan approvalrecords	In the 12 months before plan approvalrecords	Last 5 yearsrecords	Declared incidents, all yearsseparate disasters	Period	Statement
Cold Wave	22	7	1	7	0	1996 to 2026-06-30	Includes 1 Frost/Freeze record.
Drought	13	4	0	4	0	1996 to 2026-06-30
Earthquake	0	0	0	0	0		Storm Events does not record earthquakes; the USGS earthquake catalog is the source.
Hail	75	2	2	2	0	1955 to 2026-06-30
Heat Wave	12	9	0	9	0	1996 to 2026-06-30
Hurricane	0	0	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Ice Storm	3	0	1	0	0	1996 to 2026-06-30
Inland Flooding	43	5	2	2	7	1996 to 2026-06-30
Landslide	0	0	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Lightning	9	0	0	0	0	1996 to 2026-06-30
Strong Wind	216	40	21	33	2	1955 to 2026-06-30	Includes 15 High Wind and 4 Strong Wind records.
Tornado	23	2	2	2	1	1950 to 2026-06-30
Wildfire	1	0	0	0	0	1996 to 2026-06-30
Winter Weather	65	23	6	23	4	1996 to 2026-06-30	Includes 1 Sleet record.

Notable Storm Events records

Sources: 1, 6, 7

Date	Event type	Magnitude or extent	Damagenominal dollars	Deaths, injuriesdirect only	Location	Flags	Why listed
2024-01-14	Extreme Cold/Wind Chill		$0 property; $0 crops (zone total, 2024 dollars)	1, 0	NWS zone ILZ021 (GRUNDY), zone-level	new since last plan; within last 5 years	deaths or injuries recorded
2015-06-22	Tornado	EF3, 7.7 mi within this county, 1,320 yd wide	$25,000,000 property; $0 crops (2015 dollars)	0, 7	PAYTONVILLE to DIAMOND		B1-c worst recorded: Tornado
2015-06-10	Hail	2.75 in	$0 property; $0 crops (2015 dollars)	0, 0	MINOOKA		B1-c worst recorded: Hail
2015-02-14	Winter Weather		$300,000 property; $0 crops (zone total, 2015 dollars)	0, 0	NWS zone ILZ021 (GRUNDY), zone-level		B1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2014-06-30	Thunderstorm Wind	78 kt (90 mph) estimated gust	$75,000 property; $0 crops (2014 dollars)	0, 0	MORRIS		B1-c worst recorded: Thunderstorm Wind
2010-12-13	Cold/Wind Chill		$0 property; $0 crops (zone total, 2010 dollars)	1, 0	NWS zone ILZ021 (GRUNDY), zone-level		deaths or injuries recorded
2010-01-01	Cold/Wind Chill		$0 property; $0 crops (zone total, 2010 dollars)	1, 0	NWS zone ILZ021 (GRUNDY), zone-level		deaths or injuries recorded
2009-07-24	Lightning		$100,000 property; $0 crops (2009 dollars)	0, 0	MORRIS		B1-c worst recorded: Lightning
2009-06-22	Excessive Heat		$0 property; $0 crops (zone total, 2009 dollars)	1, 0	NWS zone ILZ021 (GRUNDY), zone-level		B1-c worst recorded: Excessive Heat, Heat
2005-06-15	Drought		damage not reported	0, 0	NWS zone ILZ021 (GRUNDY), zone-level		B1-c worst recorded: Drought
1997-04-06	High Wind	59 kt (68 mph), measurement type not recorded	$10,000 property; crops not reported (zone total, 1997 dollars)	0, 0	NWS zone ILZ021 (GRUNDY), zone-level		B1-c worst recorded: High Wind and Strong Wind
1996-07-17	Flash Flood		$1,000,000 property; $16,000,000 crops (1996 dollars)	0, 0	NORTHERN		B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood

The full list is in the Excel file, sheet "B1-d Storm Events history" (482 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
Cold Wave	4.89	event-days per year	about 4.89 days per year	Likely	Storm Events event-days in 15 of 30 years, 1996 to 2025 (50%)	93	2005-11-12 to 2024-11-12 (19 years)	countywide
Drought	2.18	event-days per year	about 2.18 days per year	Likely	Storm Events event-days in 5 of 30 years, 1996 to 2025 (16.7%)	77	2000 to 2025 (25.25 years; D3 and D4 only)	countywide
Earthquake	0.00152	annual probability at a location	chance a given location in the county has at least minor-damage shaking in a year: 0.152%			not shown	modeled	see B1-f	No descriptor (Storm Events does not record earthquakes).
Hail	4.09	events per year	about 4.09 per year	Highly likely	FEMA annualized frequency (modeled)	155.4 (modeled)	1986 to 2023 (38 years)	countywide
Heat Wave	4.32	event-days per year	about 4.32 days per year	Likely	Storm Events event-days in 7 of 30 years, 1996 to 2025 (23.3%)	69	2005-11-12 to 2024-11-12 (19 years)	countywide
Hurricane	0.01	events per year	about 1 in 100 years	Possible	FEMA annualized frequency (modeled)	0	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	0.817	event-days per year	about 0.817 days per year	Likely	Storm Events event-days in 3 of 30 years, 1996 to 2025 (10%)	56	1946-12-31 to 2014-02-12 (67 years)	countywide
Inland Flooding	1.25	event-days per year	about 1.25 days per year	Likely	Storm Events event-days in 22 of 30 years, 1996 to 2025 (73.3%)	35	1996 to 2023 (28 years)	see B1-f
Landslide	0.0783	events per year (modeled)	about 1 in 13 years	Possible	FEMA annualized frequency (modeled)	not shown	modeled	see B1-f
Lightning	44.2	days per year with a strike	about 44.2 days per year	Highly likely	FEMA annualized frequency (modeled)	not shown	1995 to 2023 (29 years; CONUS)	countywide
Strong Wind	5.97	events per year	about 5.97 per year	Highly likely	FEMA annualized frequency (modeled)	227	1986 to 2023 (38 years)	countywide
Tornado	0.389	events per year	about 1 in 3 years	Likely	FEMA annualized frequency (modeled)	not shown	1950 to 2023 (EF2+); 1986 to 2023 (EF0-1)	see B1-f
Wildfire	0.000143	annual probability at a location	chance a given location in the county burns in a year: 0.0143%	Possible	Storm Events records in 1 of 30 years, 1996 to 2025 (3.33%)	not shown	modeled	see B1-f
Winter Weather	14.1	event-days per year	about 14.1 days per year	Likely	Storm Events event-days in 22 of 30 years, 1996 to 2025 (73.3%)	268	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	37	30	1.23
Hail	2.00 in+	1996 to 2025	1	30	0.0333
Thunderstorm Wind (counted as NRI Strong Wind)	50-64 kt	1996 to 2025	129	30	4.3
Thunderstorm Wind (counted as NRI Strong Wind)	65 kt+	1996 to 2025	22	30	0.733
Thunderstorm Wind (counted as NRI Strong Wind)	unmeasured or below 50 kt	1996 to 2025	2	30	0.0667
Tornado	EF0-1	1996 to 2025	10	30	0.333
Tornado	EF2-3	1996 to 2025	3	30	0.1
Tornado	EF4-5	1996 to 2025	0	30	0
Tornado	unrated (EFU)	1996 to 2025	1	30	0.0333

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
Cold Wave	10 of 10	98.8	99.5	99.9	Very High 10
Drought	10 of 10	72.5	82.2	92.2	Relatively Moderate 1, Relatively Low 7, Very Low 2
Earthquake	10 of 10	50.9	63.7	73.8	Relatively Low 10
Hail	10 of 10	36.3	45.8	57.7	Relatively Low 8, Very Low 2
Heat Wave	10 of 10	40.4	52.6	74.8	Relatively Moderate 4, Relatively Low 6
Hurricane	10 of 10	15.8	22.1	34.3	Very Low 10
Ice Storm	10 of 10	28.1	37.8	56.3	Relatively Low 6, Very Low 4
Inland Flooding	10 of 10	35.4	93.2	99.3	Very High 4, Relatively High 3, Relatively Moderate 2, Relatively Low 1
Landslide	10 of 10	47.4	73.0	86.0	Relatively Low 3, Very Low 7
Lightning	10 of 10	33.6	41.1	62.6	Relatively Moderate 3, Relatively Low 7
Strong Wind	10 of 10	85.8	91.3	97.5	Very High 2, Relatively High 8
Tornado	10 of 10	77.9	86.0	97.4	Very High 3, Relatively High 7
Wildfire	10 of 10	26.9	57.9	79.1	Relatively Low 1, Very Low 9
Winter Weather	10 of 10	48.7	55.3	72.1	Relatively Moderate 10

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
Grundy County	County	Expired on 2026-04-13	FMA RL 5, SRL 5; any 33	$17,119.48	0 total; 0 since its plan	Includes $17,119.48 for declarations not counted as hazard incidents (DR-4489-IL).
Braidwood city	City	Expired on 2026-04-13	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	0 total; 0 since its plan
Carbon Hill village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	7 total; 1 since its plan
Channahon village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 2	no Public Assistance recorded	7 total; 7 since its plan	Whole community, including the part in Will County; none of its repeat-flood properties are in this county.
Coal City village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 0	$87,108.43	36 total; 0 since its plan
Diamond village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 1	$32,242.98	6 total; 1 since its plan
Dwight village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 2	no Public Assistance recorded	1 total; 0 since its plan	Whole community, including the part in Livingston County; none of its repeat-flood properties are in this county.
Kinsman village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	14 total; 2 since its plan
Mazon village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 1	$12,724.30	31 total; 3 since its plan
Morris city	City	Expired on 2026-04-13	FMA RL 1, SRL 1; any 10	$76,148.32	88 total; 5 since its plan
Seneca village	Village	Expired on 2026-04-13	FMA RL 0, SRL 1; any 1	no Public Assistance recorded	2 total; 0 since its plan	Whole community, including the part in LaSalle County; none of its repeat-flood properties are in this county.
South Wilmington village	Village	Expired on 2026-04-13	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	4 total; 0 since its 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.

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	Storm Events damage since 2021-04-14county-coded records, property plus crops, nominal dollars	Zone-level damage since planproperty plus crops, reported for the zone	Note
Cold Wave	$16,585,683,846	$174,377,036	52,475	$19	$1,320	$19,927,936	under 0.0001%		$0
Drought	n/a	$115,545,727	n/a	n/a	$101,326	n/a	0.0877% (agriculture)		$0	NRI has no building exposure for this hazard; agriculture shown
Earthquake	$28,676,357,176	n/a	52,533	$619,533	n/a	$134,983	0.00216%
Hail	$16,585,683,846	$174,377,036	52,475	$68,601	$2,667	$4,960	0.000414%	$0
Heat Wave	$16,585,683,846	$174,377,036	52,475	$5,537	$2	$586,577	under 0.0001%		$0
Hurricane	$16,585,683,846	$174,377,036	52,475	$965	$2,319	under $1	under 0.0001%
Ice Storm	$16,580,384,125	n/a	52,443	$27,124	n/a	$18,407	0.000164%
Inland Flooding	$16,572,940,437	$9,591,313	2,114	$21,998,384	$125,702	$52,152	n/a (see note)	$300,000		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	$88,203,217	n/a	242	$109	n/a	$708	0.000123%
Lightning	$16,585,683,846	n/a	52,475	$17,468	n/a	$104,984	0.000105%
Strong Wind	$16,585,683,846	$174,377,036	52,475	$999,033	$19,489	$534,782	0.00602%	$0	$0
Tornado	$16,585,683,846	$174,377,036	52,475	$2,352,535	$1,819	$2,372,044	0.0142%	$0
Wildfire	$606,264,513	$4,489,215	2,591	$9,957	$5	$587	0.00164%
Winter Weather	$16,585,683,846	$174,377,036	52,475	$8,619	$810	$37,653	under 0.0001%		$0

Totals since 2021-04-14 (Storm Events through 2026-06-30): 47 county-coded records, 47 with a damage value recorded (including $0), $300,000; 45 zone-level records, 45 with a damage value recorded (including $0), $0 reported for the zone; Public Assistance: no counted declaration since the plan.

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	52,475
Building value (total, not at risk)	$16,585,683,846
Agriculture value (total, not at risk)	$174,377,036
NRI risk rating (all hazards)	Relatively Low
Expected annual loss, buildings and agriculture, all hazards	$26,363,344
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)	$23,775,774
Social vulnerability rating	Very 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)	6	Severe repetitive loss, FMA definition (44 CFR 77.2)	6
Repetitive loss, NFIP insurance definition	42	Severe repetitive loss, NFIP insurance definition	5

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	Currently insuredproperties
County total	6	6	42	5	46	11
of which: Grundy County (unincorporated area)	5	5	31	5	33	6
of which: Diamond village	0	0	1	0	1	0
of which: Mazon village	0	0	1	0	1	1
of which: Morris city	1	1	8	0	10	3
of which: Braceville village (community ID not in plan data)	0	0	1	0	1	1
Statewide, no county in FEMA's file	0	0	5	0	5	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	Currently insuredproperties	Note
Grundy County	170256	5	5	31	5	33	6
Braidwood city	170848	0	0	0	0	0	0
Carbon Hill village	170257	0	0	0	0	0	0
Channahon village	170698	0	0	2	0	2	2	Whole community, including the part in Will County; none of its repeat-flood properties are in this county.
Coal City village	170258	0	0	0	0	0	0
Diamond village	170259	0	0	1	0	1	0
Dwight village	170423	0	0	2	0	2	1	Whole community, including the part in Livingston County; none of its repeat-flood properties are in this county.
Kinsman village	171132	0	0	0	0	0	0
Mazon village	170262	0	0	1	0	1	1
Morris city	170263	1	1	8	0	10	3
Seneca village	170407	0	1	1	1	1	0	Whole community, including the part in LaSalle County; none of its repeat-flood properties are in this county.
South Wilmington village	171013	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	Currently insuredproperties
single-family residential	6	5	39	5	42	11
2 to 4 unit residential	0	0	0	0	0	0
other residential	0	0	1	0	1	0
non-residential	0	1	2	0	3	0
not reported	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 3 properties are FMA repetitive loss but not NFIP repetitive loss, and 39 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). Grundy County, IL: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 17063). Automated baseline. https://hazardplain.org/il/17063/ 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: contact@hazardplain.org