Ozaukee County, WI: risk-assessment baseline packet, release 2026-10

Summary

Plan status as of 2026-09-30: Expired on 2025-08-31. Plan: Ozaukee County (FEMA plan 106624), approved 2020-09-01.

Since the plan was approved on 2020-09-01: no new hazard declaration and 91 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 ($17,313,471 a year), Cold Wave ($8,858,871) and Tornado ($3,473,591).

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; 55089 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 2025-08-31
Plan:: Ozaukee County (FEMA plan 106624)
Approved:: 2020-09-01
Days since expiry:: 395
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 2020-09-01)

New federal declarations:: none
Storm Events records since approval:: 91 records (data through 2026-06-30)
Repetitive loss now:: FMA RL 0, SRL 3 (44 CFR 77.2); any definition: 30
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

Source: 1

Jurisdiction	Type	Status	Plan	Approved	Expires	Days to expirynegative = days since expiry	Notes
Ozaukee County	County	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Bayside village	Village	Approved, expires 2030-11-16	Milwaukee County Hazard Mitigation Plan 2025 (FEMA plan 110750)	2025-11-17	2030-11-16	1,508	this jurisdiction approved 2026-05-04
Belgium village	Village	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Cedarburg city	City	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Fredonia village	Village	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Grafton village	Village	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Mequon city	City	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Newburg village	Village	Approved, expires 2029-12-29	Washington County 2024 Hazard Mitigation Plan (FEMA plan 110352)	2024-12-30	2029-12-29	1,186
Port Washington city	City	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Saukville village	Village	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395
Thiensville village	Village	Expired on 2025-08-31	Ozaukee County (FEMA plan 106624)	2020-09-01	2025-08-31	-395

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

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	$17,167,725	$130,113	$15,633	$17,313,471	45
2	Cold Wave	Relatively Moderate	Relatively High	$128	$59	$8,858,684	$8,858,871	34	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 Low	Relatively Moderate	$1,600,954	$2,308	$1,870,329	$3,473,591	3
4	Hail	Relatively Low	Relatively Moderate	$1,035,275	$15,303	$137,003	$1,187,581	57
5	Heat Wave	Relatively Low	Relatively Low	$30	$1	$993,661	$993,692	35
6	Strong Wind	Relatively Low	Relatively Moderate	$257,547	$24,400	$325,888	$607,835	116	Includes 13 High Wind and 42 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition).
7	Lightning	Relatively Low	Relatively Moderate	$110,360	n/a	$233,426	$343,786	19
8	Winter Weather	Relatively Low	Relatively Moderate	$1,441	$500	$105,054	$106,996	214
9	Earthquake	Very Low	Very Low	$82,640	n/a	$20,587	$103,227		Storm Events does not record earthquakes.
10	Ice Storm	Very Low	Relatively Low	$15,756	n/a	$18,532	$34,288	1
11	Wildfire	Very Low	Very Low	$13,189	$12	$1,490	$14,691	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
12	Drought	Very Low	Very Low	n/a	$11,870	n/a	$11,870	17
13	Coastal Flooding	Very Low	Very Low	$9,837	n/a	$1,030	$10,866	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
14	Hurricane	Very Low	Very Low	$758	$748	under $1	$1,507	0	No recorded events in Storm Events since 1996 (data through 2026-06-30).
15	Landslide	Very Low	Very Low	$22	n/a	$112	$135	0	Declared 1 time; no Storm Events record of this type.
	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 wildfire, 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: avalanche 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.

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
Earthquake	tract 6602.02 (Very Low, 37.6); tract 6603.01 (Very Low, 23.4); tract 6201 (Very Low, 21.8)
Hurricane	tract 6101.01 (Very Low, 24.1); tract 6101.02 (Very Low, 23.3); tract 6503 (Very Low, 21.2)
Landslide	tract 6101.01 (Very Low, 74.6); tract 6201 (Very Low, 68.7); tract 6302.01 (Very Low, 64.9)
Tornado	tract 6602.02 (Relatively High, 79.2); tract 6503 (Relatively High, 76.1); tract 6603.01 (Relatively High, 75.9)
Tsunami	no tract has a National Risk Index rating for this hazard
Wildfire	tract 6503 (Relatively Low, 76.4); tract 6101.01 (Relatively Low, 69.5); tract 6602.02 (Relatively Low, 69.3)

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 6602.02 is Census Tract 6602.02). 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
Coastal Flood, Storm Surge/Tide	none in data (flood depth: FIRM)	0					Flood depth: see the FEMA Flood Insurance Rate Map.
Cold/Wind Chill, Extreme Cold/Wind Chill	wind chill	33 records, 1996 to 2026 (33 zone-level)	1 day to 13 days (median 2 days); 28 with a recorded value	13 consecutive days, 2017-12-25 to 2018-01-06, zone-level	Cold/Wind Chill, 2007-02-03, $2,000 property; $0 crops (zone total, 2007 dollars)	Countywide (zone-level records).
Frost/Freeze (outside NRI's Cold Wave definition)	crop damage	1 record, 2017 (1 zone-level)		No crop damage reported in 1 record.		Countywide (zone-level records).
Drought	U.S. Drought Monitor scale (D0 to D4)	17 records, 2002 to 2012 (17 zone-level)	5 days to 153 days (median 69 days); 6 with a recorded value	153 days (5 months), 2005-07-01 to 2005-11-30, a run of 5 consecutive Storm Events drought records, zone-level	Drought, 2002-08-01, property not reported; $100,000 crops (zone total, 2002 dollars)	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)	71 records, 1961 to 2024	0.75 in to 3 in (median 1 in); 71 with a recorded value	3 in hail, 2004-06-23	Hail, 2006-04-13, $6,340,000 property; crops not reported (2006 dollars)	Event records naming jurisdictions in the plan: Port Washington city (11 records), Cedarburg city (9 records), Grafton village (8 records), Mequon city (6 records), Saukville village (6 records), Belgium village (5 records), Thiensville village (2 records), Bayside village (1 record), Fredonia village (1 record).
Excessive Heat, Heat	heat index (in event narratives)	35 records, 1998 to 2026 (35 zone-level)	1 day to 4 days (median 2 days); 28 with a recorded value	4 consecutive days, 2016-07-21 to 2016-07-24, 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	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)	1 record, 2008 (1 zone-level)		Ice Storm, 2008-02-17, $20,000 property; $0 crops (2008 dollars); NWS zone WIZ060		Countywide (zone-level records).
Flash Flood, Flood, Lakeshore Flood	damage and flood days (flood depth: FIRM)	45 records, 1996 to 2026 (8 zone-level)		Flood, 2004-06-01, $2,610,000 property; $5,000,000 crops (2004 dollars); NWS zone WIZ060		Event records naming jurisdictions in the plan: Port Washington city (8 records), Bayside village (5 records), Thiensville village (5 records), Mequon city (4 records), Fredonia village (2 records), Saukville village (2 records), Belgium village (1 record), Cedarburg city (1 record), Grafton village (1 record). Zone-level records (8) 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)	19 records, 1997 to 2012		Lightning, 2010-06-23, $1,000,000 property; $0 crops (2010 dollars)		Event records naming jurisdictions in the plan: Port Washington city (6 records), Grafton village (4 records), Mequon city (3 records), Cedarburg city (2 records), Bayside village (1 record), Saukville village (1 record), Thiensville 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)	55 records, 1997 to 2026 (55 zone-level)	26 kt (30 mph) to 56 kt (64 mph) (median 40 kt (46 mph)); 48 with a recorded value	56 kt (64 mph) measured gust, High Wind, 2026-03-13; NWS zone WIZ060	High Wind, 1998-11-10, $250,000 property; $25,000 crops (zone total, 1998 dollars)	Countywide (zone-level records).
Thunderstorm Wind	wind speed (kt and mph)	85 records, 1960 to 2024	50 kt (58 mph) to 70 kt (81 mph) (median 52 kt (60 mph)); 63 with a recorded value	70 kt (81 mph) estimated gust, Thunderstorm Wind, 2016-05-28	Thunderstorm Wind, 1998-05-31, $3,460,000 property; $300,000 crops (1998 dollars)	Event records naming jurisdictions in the plan: Cedarburg city (9 records), Saukville village (9 records), Thiensville village (9 records), Mequon city (7 records), Fredonia village (5 records), Grafton village (5 records), Port Washington city (5 records), Belgium village (3 records), Bayside village (1 record), Newburg village (1 record).
Tornado	Enhanced Fujita (Fujita before Feb 2007)	4 records, 1964 to 2015	F/EF0 to F/EF4 (median between F/EF0 and F/EF1); 4 with a recorded value	F4 tornado, 1964-08-22, 2.2 mi path length (whole path, pre-1996), 50 yd wide, $2,500,000 property; crops not recorded (1964 dollars), 30 direct injuries		Event records naming jurisdictions in the plan: Fredonia village (1 record), Port Washington city (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)	0
Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet	none in data (snowfall: local data)	214 records, 1996 to 2026 (214 zone-level)		Winter Storm, 2024-01-12, $20,000 property; $0 crops (2024 dollars); NWS zone WIZ060		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, 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: 13 declarations covering 10 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	Flags	Notes
2020-04-04	2020-01-20	DR-4520-WI	Major disaster	COVID-19 Pandemic	Non-natural, not counted	$2,451,852.95	in the 12 months before plan approval
2020-03-13	2020-01-20	EM-3454-WI	Emergency	COVID-19	Non-natural, not counted	no Public Assistance recorded	in the 12 months before plan approval	same incident as DR-4520
2018-10-18	2018-08-17	DR-4402-WI	Major disaster	Severe Storms, Tornadoes, Straight-Line Winds, Flooding, and Landslides	Inland Flooding (primary); also designated: Landslide, Strong Wind, Tornado	$381,221.32
2008-06-14	2008-06-05	DR-1768-WI	Major disaster	Severe Storms, Tornadoes, and Flooding	Inland Flooding; Tornado	$595,713.92
2005-09-13	2005-08-29	EM-3249-WI	Emergency	Hurricane Katrina Evacuation	Hurricane: evacuation support, not a local hazard event; not counted	no Public Assistance recorded
2004-06-18	2004-05-07	DR-1526-WI	Major disaster	Severe Storms and Flooding	Inland Flooding	$231,121.94
2001-01-24	2000-12-11	EM-3163-WI	Emergency	Snow	Winter Weather	$173,389.62
1997-07-07	1997-06-21	DR-1180-WI	Major disaster	Severe Storms and Flooding	Inland Flooding	no Public Assistance recorded
1991-08-06	1991-07-07	DR-912-WI	Major disaster	Severe Storms & Hail	Hail	no Public Assistance recorded
1986-10-07	1986-09-10	DR-775-WI	Major disaster	Severe Storms & Flooding	Inland Flooding	PA not declared for this county
1976-03-23	1976-03-23	DR-496-WI	Major disaster	Severe Storms, Icing, Wind & Flooding	Inland Flooding	no Public Assistance recorded
1973-04-27	1973-04-27	DR-376-WI	Major disaster	Severe Storms & Flooding	Inland Flooding	no Public Assistance recorded
1965-04-21	1965-04-21	DR-192-WI	Major disaster	Tornadoes, Severe Storms & Flooding	Tornado (primary); also designated: 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.

Public Assistance not placed in any Wisconsin county: 1 row, $87,788.41; listed on the Wisconsin 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
Coastal Flooding	0	0	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Cold Wave	34	7	0	5	0	1996 to 2026-06-30	Includes 1 Frost/Freeze record.
Drought	17	0	0	0	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	71	5	9	5	1	1955 to 2026-06-30
Heat Wave	35	6	0	6	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	1	0	0	0	0	1996 to 2026-06-30
Inland Flooding	45	8	8	7	8	1996 to 2026-06-30
Landslide	0	0	0	0	1	1996 to 2026-06-30	No Storm Events records of this type; 1 federal declared incident (see declarations table)
Lightning	19	0	0	0	0	1996 to 2026-06-30
Strong Wind	140	14	3	13	1	1955 to 2026-06-30	Includes 13 High Wind and 42 Strong Wind records.
Tornado	4	0	0	0	3	1950 to 2026-06-30
Tsunami	0	0	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Wildfire	0	0	0	0	0	1996 to 2026-06-30	No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events
Winter Weather	214	51	10	42	1	1996 to 2026-06-30

Notable Storm Events records

Sources: 1, 6, 7

Date	Event type	Magnitude or extent	Damagenominal dollars	Deaths, injuriesdirect only	Location	Flags	Why listed
2026-03-13	High Wind	56 kt (64 mph) measured gust	$25,000 property; $0 crops (zone total, 2026 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level	new since last plan; within last 5 years	B1-c worst recorded: High Wind and Strong Wind
2024-01-12	Winter Storm		$20,000 property; $0 crops (zone total, 2024 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level	new since last plan; within last 5 years	B1-c worst recorded: Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet
2017-12-25	Cold/Wind Chill		property not reported; $0 crops (zone total, 2017 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level		B1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill
2016-07-21	Heat		$0 property; $0 crops (zone total, 2016 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level		B1-c worst recorded: Excessive Heat, Heat
2016-05-28	Thunderstorm Wind	70 kt (81 mph) estimated gust	$20,000 property; crops not reported (2016 dollars)	0, 0	FREISTADT to THIENSVILLE		B1-c worst recorded: Thunderstorm Wind
2010-06-23	Lightning		$1,000,000 property; $0 crops (2010 dollars)	0, 0	MEQUON		B1-c worst recorded: Lightning
2008-02-17	Ice Storm		$20,000 property; $0 crops (zone total, 2008 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level		B1-c worst recorded: Ice Storm
2004-06-23	Hail	3 in	$50,000 property; crops not reported (2004 dollars)	0, 0	THIENSVILLE		B1-c worst recorded: Hail
2004-06-01	Flood		$2,610,000 property; $5,000,000 crops (zone total, 2004 dollars)	0, 0	NWS zone WIZ060 (OZAUKEE), zone-level		B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood
2001-04-05	Lightning		$20,000 property; crops not reported (2001 dollars)	0, 3	MEQUON		deaths or injuries recorded
1998-05-31	Thunderstorm Wind	speed not recorded	$3,460,000 property; $300,000 crops (1998 dollars)	0, 4	COUNTYWIDE		deaths or injuries recorded
1964-08-22	Tornado	F4, 2.2 mi path length (whole path, pre-1996), 50 yd wide	$2,500,000 property; crops not recorded (1964 dollars)	0, 30	location not recorded		deaths or injuries recorded

The full list is in the Excel file, sheet "B1-d Storm Events history" (580 rows).

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

1 Fire Management declaration (1980-04-24 to 1980-04-24) FEMA filed as Statewide with no county; each names one local fire. Listed on the state page.

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

Tribal and special-area declarations in this state are listed on the state page.

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
Coastal Flooding	0.013	events per year at a location (modeled)	about 0.013 per year at a given location in the county		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
Cold Wave	5.26	event-days per year	about 5.26 days per year	Likely	Storm Events event-days in 20 of 30 years, 1996 to 2025 (66.7%)	100	2005-11-12 to 2024-11-12 (19 years)	countywide
Drought	0.337	event-days per year	about 0.337 days per year	Likely	Storm Events event-days in 5 of 30 years, 1996 to 2025 (16.7%)	14	2000 to 2025 (25.25 years; D3 and D4 only)	countywide
Earthquake	0.000508	annual probability at a location	chance a given location in the county has at least minor-damage shaking in a year: 0.0508%			not shown	modeled	see B1-f	No descriptor (Storm Events does not record earthquakes).
Hail	2.18	events per year	about 2.18 per year	Highly likely	FEMA annualized frequency (modeled)	83.0 (modeled)	1986 to 2023 (38 years)	countywide
Heat Wave	2.21	event-days per year	about 2.21 days per year	Likely	Storm Events event-days in 14 of 30 years, 1996 to 2025 (46.7%)	37	2005-11-12 to 2024-11-12 (19 years)	countywide
Hurricane	0.00667	events per year	about 1 in 150 years	Unlikely	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	0.325	event-days per year	about 0.325 days per year	Possible	Storm Events event-days in 1 of 30 years, 1996 to 2025 (3.33%)	5	1946-12-31 to 2014-02-12 (67 years)	countywide
Inland Flooding	1.04	event-days per year	about 1.04 days per year	Likely	Storm Events event-days in 18 of 30 years, 1996 to 2025 (60%)	29	1996 to 2023 (28 years)	see B1-f
Landslide	0.0368	events per year (modeled)	about 1 in 27 years	Possible	FEMA annualized frequency (modeled)	not shown	modeled	see B1-f
Lightning	32.1	days per year with a strike	about 32.1 days per year	Highly likely	FEMA annualized frequency (modeled)	not shown	1995 to 2023 (29 years; CONUS)	countywide
Strong Wind	2.44	events per year	about 2.44 per year	Highly likely	FEMA annualized frequency (modeled)	20	1986 to 2023 (38 years)	countywide
Tornado	0.372	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
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	0.0000838	annual probability at a location	chance a given location in the county burns in a year: 0.00838%		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
Winter Weather	15.7	event-days per year	about 15.7 days per year	Highly likely	Storm Events event-days in 29 of 30 years, 1996 to 2025 (96.7%)	298	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	28	30	0.933
Hail	2.00 in+	1996 to 2025	3	30	0.1
Thunderstorm Wind (counted as NRI Strong Wind)	50-64 kt	1996 to 2025	51	30	1.7
Thunderstorm Wind (counted as NRI Strong Wind)	65 kt+	1996 to 2025	3	30	0.1
Thunderstorm Wind (counted as NRI Strong Wind)	unmeasured or below 50 kt	1996 to 2025	7	30	0.233
Tornado	EF0-1	1996 to 2025	3	30	0.1
Tornado	EF2-3	1996 to 2025	0	30	0
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
Coastal Flooding	8 of 21	68.0	75.5	82.7	Relatively Low 3, Very Low 5, No Rating 13
Cold Wave	21 of 21	72.5	89.5	96.3	Very High 3, Relatively High 15, Relatively Moderate 3
Drought	14 of 21	67.7	72.7	82.8	Relatively Low 4, Very Low 10, No Rating 7
Earthquake	21 of 21	4.0	12.0	37.6	Very Low 21
Hail	21 of 21	63.6	80.5	90.6	Relatively High 1, Relatively Moderate 16, Relatively Low 4
Heat Wave	21 of 21	19.6	45.0	66.1	Relatively Moderate 7, Relatively Low 14
Hurricane	21 of 21	12.4	15.3	24.1	Very Low 21
Ice Storm	21 of 21	5.1	14.8	32.6	Very Low 21
Inland Flooding	21 of 21	4.9	35.7	92.9	Relatively High 5, Relatively Moderate 5, Relatively Low 7, Very Low 4
Landslide	21 of 21	13.2	44.2	74.6	Very Low 21
Lightning	21 of 21	26.3	50.8	72.0	Relatively Moderate 11, Relatively Low 10
Strong Wind	21 of 21	32.1	58.1	74.9	Relatively Moderate 11, Relatively Low 10
Tornado	21 of 21	43.5	64.0	79.2	Relatively High 3, Relatively Moderate 13, Relatively Low 5
Tsunami	0 of 21				Insufficient Data 21
Wildfire	21 of 21	22.9	51.5	76.4	Relatively Low 3, Very Low 18
Winter Weather	21 of 21	38.9	58.1	73.3	Relatively Moderate 16, Relatively Low 5

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
Ozaukee County	County	Expired on 2025-08-31	FMA RL 0, SRL 0; any 1	$51,247.19	0 total; 0 since its plan
Bayside village	Village	Approved, expires 2030-11-16	FMA RL 0, SRL 0; any 2	no Public Assistance recorded	8 total; 1 since its plan	Whole community, including the part in Milwaukee County; none of its repeat-flood properties are in this county.
Belgium village	Village	Expired on 2025-08-31	FMA RL 0, SRL 0; any 0	$7,876.62	9 total; 0 since its plan
Cedarburg city	City	Expired on 2025-08-31	FMA RL 0, SRL 0; any 0	$35,026.77	21 total; 1 since its plan
Fredonia village	Village	Expired on 2025-08-31	FMA RL 0, SRL 0; any 0	$10,408.43	9 total; 1 since its plan
Grafton village	Village	Expired on 2025-08-31	FMA RL 0, SRL 0; any 0	$147,699.11	18 total; 2 since its plan	Includes $66,750.10 for declarations not counted as hazard incidents (DR-4520-WI).
Mequon city	City	Expired on 2025-08-31	FMA RL 0, SRL 2; any 16	$503,093.98	20 total; 0 since its plan
Newburg village	Village	Approved, expires 2029-12-29	FMA RL 0, SRL 0; any 0	no Public Assistance recorded	1 total; 0 since its plan
Port Washington city	City	Expired on 2025-08-31	FMA RL 0, SRL 0; any 0	$215,620.22	31 total; 1 since its plan
Saukville village	Village	Expired on 2025-08-31	FMA RL 0, SRL 1; any 2	$134,970.50	18 total; 0 since its plan
Thiensville village	Village	Expired on 2025-08-31	FMA RL 0, SRL 0; any 11	$131,983.73	17 total; 2 since its plan

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

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 2020-09-01county-coded records, property plus crops, nominal dollars	Zone-level damage since planproperty plus crops, reported for the zone	Note
Coastal Flooding	$1,170,529,262	n/a	3,259	$9,837	n/a	$1,030	0.00084%
Cold Wave	$26,151,883,529	$96,853,986	91,247	$128	$59	$8,858,684	under 0.0001%		$0
Drought	n/a	$7,126,985	n/a	n/a	$11,870	n/a	0.167% (agriculture)			NRI has no building exposure for this hazard; agriculture shown
Earthquake	$44,029,875,647	n/a	91,503	$82,640	n/a	$20,587	0.000188%
Hail	$26,151,883,529	$96,853,986	91,247	$1,035,275	$15,303	$137,003	0.00396%	$0
Heat Wave	$26,151,883,529	$96,853,986	91,247	$30	$1	$993,661	under 0.0001%		$0
Hurricane	$26,151,883,529	$96,853,986	91,247	$758	$748	under $1	under 0.0001%
Ice Storm	$26,101,921,096	n/a	90,948	$15,756	n/a	$18,532	under 0.0001%
Inland Flooding	$26,124,070,024	$4,892,435	2,389	$17,167,725	$130,113	$15,633	n/a (see note)	$519,000		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	$141,359,520	n/a	499	$22	n/a	$112	under 0.0001%
Lightning	$26,151,883,529	n/a	91,247	$110,360	n/a	$233,426	0.000422%
Strong Wind	$26,151,883,529	$96,853,986	91,247	$257,547	$24,400	$325,888	0.000985%	$77,000	$42,000	Storm Events damage since the plan includes 2 zone-level High Wind records ($30,000) and 2 zone-level Strong Wind records ($12,000): NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition.
Tornado	$26,151,883,529	$96,853,986	91,247	$1,600,954	$2,308	$1,870,329	0.00612%
Tsunami	n/a	n/a	n/a	n/a	n/a	n/a				NRI publishes no building exposure for this county
Wildfire	$2,469,031,701	$16,910,134	12,451	$13,189	$12	$1,490	0.000534%
Winter Weather	$26,151,883,529	$96,853,986	91,247	$1,441	$500	$105,054	under 0.0001%		$35,000

Totals since 2020-09-01 (Storm Events through 2026-06-30): 23 county-coded records, 23 with a damage value recorded (including $0), $596,000; 68 zone-level records, 68 with a damage value recorded (including $0), $77,000 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	91,247
Building value (total, not at risk)	$26,151,883,529
Agriculture value (total, not at risk)	$96,853,986
NRI risk rating (all hazards)	Relatively Low
Expected annual loss, buildings and agriculture, all hazards	$20,480,977
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)	$12,581,428
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)	0	Severe repetitive loss, FMA definition (44 CFR 77.2)	3
Repetitive loss, NFIP insurance definition	30	Severe repetitive loss, NFIP insurance definition	3

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	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Currently insuredproperties
County total	3	30	3	30	13
of which: Ozaukee County (unincorporated area)	0	1	0	1	1
of which: Saukville village	1	2	1	2	0
of which: Thiensville village	0	11	0	11	1
of which: Mequon city	2	16	2	16	11
Statewide, no county in FEMA's file	0	2	0	2	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	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Currently insuredproperties	Note
Ozaukee County	550310	0	1	0	1	1
Bayside village	550270	0	2	0	2	0	Whole community, including the part in Milwaukee County; none of its repeat-flood properties are in this county.
Belgium village	550311	0	0	0	0	0
Cedarburg city	550312	0	0	0	0	0
Fredonia village	550313	0	0	0	0	0
Grafton village	550314	0	0	0	0	0
Mequon city	555564	2	16	2	16	11
Newburg village	550056	0	0	0	0	0
Port Washington city	550316	0	0	0	0	0
Saukville village	550317	1	2	1	2	0
Thiensville village	550318	0	11	0	11	1

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	SRL, FMAproperties	RL, NFIPproperties	SRL, NFIPproperties	Any categoryproperties	Currently insuredproperties
single-family residential	3	20	3	20	13
2 to 4 unit residential	0	1	0	1	0
other residential	0	8	0	8	0
non-residential	0	1	0	1	0
not reported	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 30 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). Ozaukee County, WI: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 55089). Automated baseline. https://hazardplain.org/wi/55089/ 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