Summary
Plan status as of 2026-09-30: Expired on 2010-07-12. Plan: Washtenaw County (FEMA plan 101029), approved 2005-07-13.
Since the plan was approved on 2005-07-13: 2 new hazard declarations (2 incidents): DR-4607-MI (Severe Storms, Flooding, and Tornadoes), DR-4925-MI (Severe Storms, Tornadoes, and Flooding); also 1 evacuation-support declaration (not counted), 2 COVID-19 declarations (not counted).
NOAA Storm Events records since that date: 515 records (data through 2026-06-30).
Highest expected annual loss (FEMA National Risk Index, modeled total; see B1-a): Inland Flooding ($46,633,134 a year), Tornado ($20,847,641) and Cold Wave ($10,696,760).
Repetitive-loss flood properties now: FMA RL 1, SRL 1 (44 CFR 77.2); any definition: 10.
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.
Plan clock
- Status:
- Expired on 2010-07-12
- Plan:
- Washtenaw County (FEMA plan 101029)
- Approved:
- 2005-07-13
- Days since expiry:
- 5,924
- 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 2005-07-13)
- New federal declarations:
- 2 new hazard declarations (2 incidents): DR-4607-MI (Severe Storms, Flooding, and Tornadoes), DR-4925-MI (Severe Storms, Tornadoes, and Flooding); also 1 evacuation-support declaration (not counted), 2 COVID-19 declarations (not counted)
- Storm Events records since approval:
- 515 records (data through 2026-06-30)
- Repetitive loss now:
- FMA RL 1, SRL 1 (44 CFR 77.2); any definition: 10
- 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: 32 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 |
|---|---|---|---|---|---|---|
| Washtenaw County | County | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Ann Arbor city | City | Approved, expires 2027-12-06 | City of Ann Arbor HMP Update (FEMA plan 108521) | 2022-12-07 | 2027-12-06 | 432 |
| Barton Hills village | Village | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Chelsea city | City | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Dexter city | City | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Manchester village | Village | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Milan city | City | Expired on 2022-07-13 | Monroe County (FEMA plan 101035) | 2017-07-14 | 2022-07-13 | -1,540 |
| Saline city | City | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Whitmore Lake CDP | Unincorporated | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Ypsilanti city | City | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Ann Arbor charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Augusta charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Bridgewater township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Dexter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Freedom township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Lima township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Lodi township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Lyndon township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Manchester township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Northfield township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Pittsfield charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Salem township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Saline township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Scio township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Sharon township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Superior charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Sylvan township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Webster township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| York charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Ypsilanti charter township | Township | Expired on 2010-07-12 | Washtenaw County (FEMA plan 101029) | 2005-07-13 | 2010-07-12 | -5,924 |
| Eastern Michigan University | College/University | Approved, expires 2030-05-20 | Eastern Michigan University 2025 Hazard Mitigation Plan (FEMA plan 110550) | 2025-05-21 | 2030-05-20 | 1,328 |
| University of Michigan (Ann Arbor & Dearborn Campus) | College/University | Expired on 2024-10-30 | University of Michigan (Ann Arbor & Dearborn Campus) (FEMA plan 105977) | 2019-10-31 | 2024-10-30 | -700 |
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 Moderate | Relatively Moderate | $46,578,651 | $14,314 | $40,170 | $46,633,134 | 38 | |
| 2 | Tornado | Relatively High | Relatively High | $11,986,074 | $998 | $8,860,570 | $20,847,641 | 7 | |
| 3 | Cold Wave | Relatively High | Relatively High | $33,880 | $65,489 | $10,597,390 | $10,696,760 | 16 | Includes 2 Frost/Freeze records (outside NRI's Cold Wave definition; counted in this table and in B1-d, not in the B1-e descriptor). |
| 4 | Strong Wind | Relatively High | Relatively High | $4,568,086 | $40,688 | $1,518,153 | $6,126,926 | 420 | Includes 39 High Wind and 5 Strong Wind records (NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition). |
| 5 | Heat Wave | Relatively Moderate | Relatively Moderate | $25,466 | $1 | $2,873,304 | $2,898,771 | 15 | |
| 6 | Hail | Relatively Moderate | Relatively Moderate | $1,383,782 | $46,546 | $49,830 | $1,480,159 | 223 | |
| 7 | Lightning | Relatively High | Relatively High | $113,334 | n/a | $1,178,641 | $1,291,974 | 21 | |
| 8 | Earthquake | Relatively Low | Relatively Low | $1,039,259 | n/a | $231,873 | $1,271,132 | Storm Events does not record earthquakes. | |
| 9 | Ice Storm | Relatively High | Relatively High | $1,111,180 | n/a | $53,821 | $1,165,001 | 4 | |
| 10 | Winter Weather | Relatively Moderate | Relatively Moderate | $136,867 | $405 | $41,255 | $178,527 | 62 | |
| 11 | Hurricane | Very Low | Very Low | $69,014 | $3,840 | $461 | $73,315 | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). |
| 12 | Wildfire | Very Low | Very Low | $34,939 | $6 | $3,255 | $38,200 | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). |
| 13 | Landslide | Relatively Low | Very Low | $2,439 | n/a | $4,589 | $7,028 | 0 | No recorded events in Storm Events since 1996 (data through 2026-06-30). |
| 14 | Drought | No Rating | No Expected Annual Losses | n/a | $0 | n/a | $0 | 2 |
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 and landslide 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, 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 4234 (Relatively Low, 60.8); tract 9801.01 (Relatively Low, 53.3); tract 9840 (Relatively Low, 49.1) |
| Hurricane | tract 9801.01 (Very Low, 48.3); tract 4070 (Very Low, 41.0); tract 4060 (Very Low, 40.4) |
| Landslide | tract 4320 (Relatively Low, 93.1); tract 4310 (Relatively Low, 91.7); tract 4440 (Relatively Low, 90.9) |
| Tornado | tract 9801.01 (Very High, 99.3); tract 4550 (Relatively High, 92.4); tract 4234 (Relatively High, 92.1) |
| Wildfire | tract 4440 (Relatively Low, 72.7); tract 4610 (Relatively Low, 71.1); tract 4202 (Relatively Low, 70.2) |
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 4234 is Census Tract 4234). 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 | 14 records, 1996 to 2026 (14 zone-level) | 1 day to 21 days (median 2.5 days); 14 with a recorded value | January 2003 (1 monthly summary record), zone-level | Extreme Cold/Wind Chill, 2000-12-21, $475,000 property; crops not reported, reported for the zone (2000 dollars) | Countywide (zone-level records). | Wind chill: in event narratives only (local data needed). |
| Frost/Freeze (outside NRI's Cold Wave definition) | crop damage | 2 records, 2007 to 2012 (2 zone-level) | Frost/Freeze, 2012-04-27, $1,300,000 crop damage (2012 dollars); NWS zone MIZ075 | Countywide (zone-level records). | Temperature: in event narratives only (local data needed). | ||
| Drought | U.S. Drought Monitor scale (D0 to D4) | 2 records, 2001 to 2002 (2 zone-level) | 30 days to 31 days (median 30.5 days); 2 with a recorded value | 31 days (1 month), 2001-07-01 to 2001-07-31, 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) | 261 records, 1957 to 2026 | 0.75 in to 3 in (median 0.88 in); 261 with a recorded value | 3 in hail, 2000-05-09 | Hail, 2023-06-15, $500,000 property; $0 crops (2023 dollars) | Event records naming jurisdictions in the plan: Ann Arbor charter township (39 records), Ann Arbor city (39 records), Saline city (26 records), Saline township (26 records), Ypsilanti charter township (20 records), Ypsilanti city (20 records), Chelsea city (19 records), Dexter city (15 records), Dexter township (15 records), Milan city (10 records); and 10 more jurisdictions (see the Excel file). | |
| Excessive Heat, Heat | heat index (in event narratives) | 15 records, 1999 to 2026 (15 zone-level) | 1 day to 7 days (median 5 days); 11 with a recorded value | 7 consecutive days, 2012-07-01 to 2012-07-07, zone-level | Countywide (zone-level records). | Heat index: in event narratives only (local data needed). 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) | 4 records, 1997 to 2023 (4 zone-level) | Ice Storm, 2023-02-22, $8,000,000 property; $0 crops (2023 dollars); NWS zone MIZ075 | Countywide (zone-level records). | Ice thickness: in event narratives only (local data needed). | ||
| Flash Flood, Flood, Lakeshore Flood | damage and flood days (flood depth: FIRM) | 38 records, 1996 to 2025 (14 zone-level) | Flash Flood, 2021-06-25, $7,500,000 property; $0 crops (2021 dollars) | Event records naming jurisdictions in the plan: Ann Arbor charter township (6 records), Ann Arbor city (6 records), Salem township (3 records), Chelsea city (2 records), Manchester township (2 records), Manchester village (2 records), Saline city (2 records), Saline township (2 records), Scio township (2 records), Dexter city (1 record); and 1 more jurisdiction (see the Excel file). Zone-level records (14) 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 | Physical measure: in event narratives only (local data needed). | ||||
| Lightning | annualized frequency (the measure FEMA's Local Mitigation Planning Handbook names) | 21 records, 1997 to 2014 | Lightning, 2014-06-18, $0 property; $0 crops (2014 dollars), 1 direct death | Lightning, 2000-12-11, $1,100,000 property; crops not reported (2000 dollars) | Event records naming jurisdictions in the plan: Ann Arbor charter township (5 records), Ann Arbor city (5 records), Ypsilanti charter township (4 records), Ypsilanti city (4 records), Saline city (3 records), Saline township (3 records), Chelsea city (2 records), Dexter city (1 record), Dexter township (1 record), Lima township (1 record); and 3 more jurisdictions (see the Excel file). | Storm Events lists lightning with damage or casualties; physical measure in event narratives only (local data needed). | |
| High Wind and Strong Wind (outside NRI's Strong Wind definition) | wind speed (kt and mph) | 44 records, 1996 to 2026 (44 zone-level) | 35 kt (40 mph) to 76 kt (87 mph) (median 52 kt (60 mph)); 42 with a recorded value | 76 kt (87 mph) measured gust, High Wind, 2003-11-12; NWS zone MIZ075 | High Wind, 2017-03-08, $25,000,000 property; $0 crops, reported for the zone (2017 dollars) | Countywide (zone-level records). | |
| Thunderstorm Wind | wind speed (kt and mph) | 494 records, 1957 to 2026 | 48 kt (55 mph) to 80 kt (92 mph) (median 52 kt (60 mph)); 429 with a recorded value | 80 kt (92 mph), measurement type not recorded, Thunderstorm Wind, 1990-01-25 | Thunderstorm Wind, 1998-07-21, $4,500,000 property; crops not reported (1998 dollars) | Event records naming jurisdictions in the plan: Ann Arbor charter township (60 records), Ann Arbor city (60 records), Saline city (33 records), Saline township (33 records), Dexter city (32 records), Dexter township (32 records), Ypsilanti charter township (31 records), Ypsilanti city (31 records), Chelsea city (29 records), Manchester township (26 records); and 9 more jurisdictions (see the Excel file). | |
| Tornado | Enhanced Fujita (Fujita before Feb 2007) | 29 records, 1951 to 2026 | F/EF0 to F/EF3 (median F/EF1); 29 with a recorded value | F3 tornado, 1953-06-08, 11.3 mi path length (whole path, pre-1996), 70 yd wide, $25,000 property; crops not recorded (1953 dollars), 1 direct death, 5 direct injuries | Tornado, 2012-03-15, $12,000,000 property; $0 crops (2012 dollars) | Event records naming jurisdictions in the plan: Ann Arbor charter township (2 records), Ann Arbor city (2 records), Bridgewater township (1 record), Salem township (1 record), Scio township (1 record), York charter township (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) | 0 | Acres burned: in event narratives only (local data needed). | ||||
| Winter Storm, Heavy Snow, Blizzard, Lake-Effect Snow, Winter Weather, Sleet | none in data (snowfall: local data) | 62 records, 1996 to 2024 (62 zone-level) | Winter Storm, 2018-04-14, $6,000,000 property; $0 crops (2018 dollars); NWS zone MIZ075 | Countywide (zone-level records). | Snow depth: in event narratives only (local data needed). |
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".
Storm Events records are more complete after 1996; before 1996 only Tornado (from 1950), Hail and Thunderstorm Wind (from 1955) exist. Zone-level records whose zone 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.
A monthly summary record covers most or all of a month; it does not count days at wave conditions.
Supports FEMA checklist item B1-d: previous occurrences
Federal declarations for this county: 12 declarations covering 8 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 |
|---|---|---|---|---|---|---|---|---|
| 2026-06-30 | 2026-04-10 | DR-4925-MI | Major disaster | Severe Storms, Tornadoes, and Flooding | Inland Flooding (primary); also designated: Tornado | PA not declared for this county | new since last plan; within last 5 years | |
| 2021-07-15 | 2021-06-25 | DR-4607-MI | Major disaster | Severe Storms, Flooding, and Tornadoes | Inland Flooding; Tornado | PA not declared for this county | new since last plan | |
| 2020-03-27 | 2020-01-20 | DR-4494-MI | Major disaster | COVID-19 Pandemic | Non-natural, not counted | $11,738,251.45 | new since last plan | |
| 2020-03-13 | 2020-01-20 | EM-3455-MI | Emergency | COVID-19 | Non-natural, not counted | no Public Assistance recorded | new since last plan | same incident as DR-4494 |
| 2005-09-07 | 2005-08-29 | EM-3225-MI | Emergency | Hurricane Katrina Evacuation | Hurricane: evacuation support, not a local hazard event; not counted | $59,003.66 | new since last plan | |
| 2004-06-30 | 2004-05-20 | DR-1527-MI | Major disaster | Severe Storms, Tornadoes, and Flooding | Inland Flooding; Tornado | PA not declared for this county | ||
| 2003-09-23 | 2003-08-14 | EM-3189-MI | Emergency | Power Outage | Non-natural, not counted | $129,927.85 | ||
| 2001-01-10 | 2000-12-11 | EM-3160-MI | Emergency | Snow | Winter Weather | $396,804.30 | ||
| 1999-01-27 | 1999-01-02 | EM-3137-MI | Emergency | Mi - Severe Weather 1/2 /99 | Winter Weather | $302,496.07 | ||
| 1980-09-08 | 1980-09-08 | DR-631-MI | Major disaster | Severe Storms & Flooding | Inland Flooding | no Public Assistance recorded | ||
| 1978-01-27 | 1978-01-27 | EM-3057-MI | Emergency | Blizzards & Snowstorms | Winter Weather | no Public Assistance recorded | ||
| 1965-04-14 | 1965-04-14 | DR-190-MI | Major disaster | Tornadoes & Severe Storms | Tornado | no Public Assistance recorded |
School districts and special districts in this county: $1,137,560.74 (included in the county total above). Public Assistance matched by applicant name to the school districts and special districts FEMA lists as plan participants in this county. They have no row of their own in the jurisdiction table, so their total is listed here. These dollars are already included in the county PA column of the declarations table (the FEMA record places each applicant in this county), so this line is not added to it.
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 |
|---|---|---|---|---|---|
| 1956-04-05 | 1956-04-05 | DR-53-MI | Major disaster | Tornado | Tornado |
| 1953-06-09 | 1953-06-09 | DR-6-MI | Major disaster | Tornado | Tornado |
| 1953-06-02 | 1953-06-02 | DR-4-MI | Major disaster | Tornado | Tornado |
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) | Since plan approvalrecords | In the 12 months before plan approvalrecords | Last 5 yearsrecords | Declared incidents, all yearsseparate disasters | Declared since approvalseparate disasters | Period | Statement |
|---|---|---|---|---|---|---|---|---|
| Cold Wave | 16 | 10 | 0 | 1 | 0 | 0 | 1996 to 2026-06-30 | Includes 2 Frost/Freeze records. |
| Drought | 2 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Earthquake | 0 | 0 | 0 | 0 | 0 | 0 | Storm Events does not record earthquakes; the USGS earthquake catalog is the source. | |
| Hail | 261 | 143 | 5 | 20 | 0 | 0 | 1955 to 2026-06-30 | |
| Heat Wave | 15 | 11 | 0 | 1 | 0 | 0 | 1996 to 2026-06-30 | |
| Hurricane | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Ice Storm | 4 | 2 | 0 | 1 | 0 | 0 | 1996 to 2026-06-30 | |
| Inland Flooding | 38 | 17 | 1 | 3 | 4 | 2 | 1996 to 2026-06-30 | |
| Landslide | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Lightning | 21 | 5 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | |
| Strong Wind | 538 | 281 | 8 | 41 | 0 | 0 | 1955 to 2026-06-30 | Includes 39 High Wind and 5 Strong Wind records. |
| Tornado | 29 | 7 | 0 | 1 | 4 | 2 | 1950 to 2026-06-30 | |
| Wildfire | 0 | 0 | 0 | 0 | 0 | 0 | 1996 to 2026-06-30 | No recorded events, 1996 to 2026-06-30, NOAA NCEI Storm Events |
| Winter Weather | 62 | 39 | 3 | 4 | 3 | 0 | 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 |
|---|---|---|---|---|---|---|---|
| 2026-01-23 | Extreme Cold/Wind Chill | $0 property; $0 crops, reported for the zone (2026 dollars) | 1, 0 | NWS zone MIZ075 (WASHTENAW), zone-level | new since last plan; within last 5 years | deaths or injuries recorded | |
| 2023-02-22 | Ice Storm | $8,000,000 property; $0 crops, reported for the zone (2023 dollars) | 0, 0 | NWS zone MIZ075 (WASHTENAW), zone-level | new since last plan; within last 5 years | B1-c worst recorded: Ice Storm | |
| 2021-06-25 | Flash Flood | $7,500,000 property; $0 crops (2021 dollars) | 0, 0 | LYNDON CENTER to ROWES CORNER | new since last plan | B1-c worst recorded: Flash Flood, Flood, Lakeshore Flood | |
| 2014-06-18 | Lightning | $0 property; $0 crops (2014 dollars) | 1, 0 | GEDDES | new since last plan | B1-c worst recorded: Lightning | |
| 2012-07-01 | Heat | $0 property; $0 crops, reported for the zone (2012 dollars) | 0, 5 | NWS zone MIZ075 (WASHTENAW), zone-level | new since last plan | B1-c worst recorded: Excessive Heat, Heat | |
| 2012-04-27 | Frost/Freeze | $0 property; $1,300,000 crops, reported for the zone (2012 dollars) | 0, 0 | NWS zone MIZ075 (WASHTENAW), zone-level | new since last plan | B1-c worst recorded: Frost/Freeze | |
| 2003-11-12 | High Wind | 76 kt (87 mph) measured gust | $2,000,000 property; crops not reported, reported for the zone (2003 dollars) | 0, 0 | NWS zone MIZ075 (WASHTENAW), zone-level | B1-c worst recorded: High Wind and Strong Wind | |
| 2003-01-10 | Cold/Wind Chill | damage not reported | 0, 0 | NWS zone MIZ075 (WASHTENAW), zone-level | B1-c worst recorded: Cold/Wind Chill, Extreme Cold/Wind Chill | ||
| 2002-09-19 | Lightning | damage not reported | 1, 2 | ANN ARBOR | deaths or injuries recorded | ||
| 2000-05-09 | Hail | 3 in | damage not reported | 0, 0 | SALINE | B1-c worst recorded: Hail | |
| 1990-01-25 | Thunderstorm Wind | 80 kt (92 mph), measurement type not recorded | damage not recorded (pre-1996 record) | 0, 0 | location not recorded | B1-c worst recorded: Thunderstorm Wind | |
| 1953-06-08 | Tornado | F3, 11.3 mi path length (whole path, pre-1996), 70 yd wide | $25,000 property; crops not recorded (1953 dollars) | 1, 5 | location not recorded | deaths or injuries recorded |
The full list is in the Excel file, sheet "B1-d Storm Events history" (986 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).
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 |
|---|---|---|---|---|---|---|---|---|---|
| Cold Wave | 2.79 | event-days per year | about 2.79 days per year | Likely (from Storm Events: 11 of 30 years) | event-days in 11 of 30 years, 1996 to 2025 (36.7%) | 53 | 2005-11-12 to 2024-11-12 (19 years) | countywide | |
| Drought | 0 | event-days per year | none modeled | Possible (from Storm Events: 2 of 30 years) | event-days in 2 of 30 years, 1996 to 2025 (6.67%) | 0 | 2000 to 2025 (25.25 years; D3 and D4 only) | countywide | NRI models no drought event-days here (2000 to 2025, 25.25 years; D3 and D4 only); Storm Events has a record in 2 of 30 years. The descriptor comes from Storm Events, which counts D2 drought that NRI leaves out. |
| Earthquake | 0.000956 | annual probability at a location | chance a given location in the county has at least minor-damage shaking in a year: 0.0956% | not shown | modeled | see B1-f | No descriptor (Storm Events does not record earthquakes). | ||
| Hail | 3.14 | events per year | about 3.14 per year | Highly likely | FEMA annualized frequency (modeled) | 119.3 (modeled) | 1986 to 2023 (38 years) | countywide | |
| Heat Wave | 3.68 | event-days per year | about 3.68 days per year | Likely (from Storm Events: 9 of 30 years) | event-days in 9 of 30 years, 1996 to 2025 (30%) | 56 | 2005-11-12 to 2024-11-12 (19 years) | countywide | |
| Hurricane | 0.00896 | events per year | about 1 in 112 years | Unlikely | FEMA annualized frequency (modeled) | 2 | 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 | 1.78 | event-days per year | about 1.78 days per year | Likely (from Storm Events: 4 of 30 years) | event-days in 4 of 30 years, 1996 to 2025 (13.3%) | 120 | 1946-12-31 to 2014-02-12 (67 years) | countywide | |
| Inland Flooding | 1.18 | event-days per year | about 1.18 days per year | Likely (from Storm Events: 20 of 30 years) | event-days in 20 of 30 years, 1996 to 2025 (66.7%) | 33 | 1996 to 2023 (28 years) | see B1-f | |
| Landslide | 0.184 | events per year (modeled) | about 1 in 5 years | Likely | FEMA annualized frequency (modeled) | not shown | modeled | see B1-f | |
| Lightning | 36.9 | days per year with a strike | about 36.9 days per year | Highly likely | FEMA annualized frequency (modeled) | not shown | 1995 to 2023 (29 years; CONUS) | countywide | |
| Strong Wind | 5.7 | events per year | about 5.7 per year | Highly likely | FEMA annualized frequency (modeled) | 217 | 1986 to 2023 (38 years) | countywide | |
| Tornado | 0.348 | 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 | 0.0000187 | annual probability at a location | chance a given location in the county burns in a year: 0.00187% | 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 | 10.5 | event-days per year | about 10.5 days per year | Highly likely (from Storm Events: 27 of 30 years) | event-days in 27 of 30 years, 1996 to 2025 (90%) | 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 | 103 | 30 | 3.43 |
| Hail | 2.00 in+ | 1996 to 2025 | 7 | 30 | 0.233 |
| Thunderstorm Wind (counted as NRI Strong Wind) | 50-64 kt | 1996 to 2025 | 359 | 30 | 12 |
| Thunderstorm Wind (counted as NRI Strong Wind) | 65 kt+ | 1996 to 2025 | 11 | 30 | 0.367 |
| 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 | 5 | 30 | 0.167 |
| 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 | ||
|---|---|---|---|---|---|
| Min | Median | Max | |||
| Cold Wave | 107 of 107 | 15.7 | 61.4 | 85.7 | Relatively High 9, Relatively Moderate 81, Relatively Low 14, Very Low 3 |
| Drought | 0 of 107 | No Rating 107 | |||
| Earthquake | 107 of 107 | 4.1 | 26.9 | 60.8 | Relatively Low 11, Very Low 96 |
| Hail | 107 of 107 | 14.0 | 54.7 | 89.5 | Relatively High 1, Relatively Moderate 13, Relatively Low 87, Very Low 6 |
| Heat Wave | 107 of 107 | 1.6 | 30.9 | 66.6 | Relatively Moderate 6, Relatively Low 86, Very Low 15 |
| Hurricane | 107 of 107 | 13.2 | 28.5 | 48.3 | Very Low 107 |
| Ice Storm | 107 of 107 | 3.7 | 61.0 | 96.0 | Relatively High 1, Relatively Moderate 34, Relatively Low 68, Very Low 4 |
| Inland Flooding | 107 of 107 | 0.3 | 19.3 | 86.1 | Relatively High 4, Relatively Moderate 13, Relatively Low 51, Very Low 39 |
| Landslide | 106 of 107 | 12.8 | 45.1 | 93.1 | Relatively Low 12, Very Low 94, No Rating 1 |
| Lightning | 107 of 107 | 0.4 | 44.4 | 80.7 | Relatively High 1, Relatively Moderate 39, Relatively Low 64, Very Low 3 |
| Strong Wind | 107 of 107 | 11.9 | 73.5 | 99.1 | Very High 1, Relatively High 26, Relatively Moderate 69, Relatively Low 9, Very Low 2 |
| Tornado | 107 of 107 | 9.3 | 65.3 | 99.3 | Very High 1, Relatively High 28, Relatively Moderate 64, Relatively Low 12, Very Low 2 |
| Wildfire | 105 of 107 | 20.9 | 44.2 | 72.7 | Relatively Low 6, Very Low 99, No Rating 2 |
| Winter Weather | 107 of 107 | 14.9 | 34.3 | 80.8 | Relatively High 1, Relatively Moderate 14, Relatively Low 90, Very Low 2 |
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, 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.
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 |
|---|---|---|---|---|---|---|
| Washtenaw County | County | Expired on 2010-07-12 | $2,585,568.23 | 0 total; 0 since its plan | No NFIP community ID on this jurisdiction's plan row. Includes $2,585,568.23 for declarations not counted as hazard incidents (DR-4494-MI, EM-3189-MI, EM-3225-MI). | |
| Ann Arbor city | City | Approved, expires 2027-12-06 | FMA RL 0, SRL 1; any 4 | $179,372.54 | 112 total; 13 since its plan | Includes $31,966.50 for declarations not counted as hazard incidents (EM-3189-MI). |
| Barton Hills village | Village | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Chelsea city | City | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | $14,692.80 | 52 total; 20 since its plan | |
| Dexter city | City | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 49 total; 24 since its plan | |
| Manchester village | Village | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 36 total; 13 since its plan | |
| Milan city | City | Expired on 2022-07-13 | FMA RL 0, SRL 0; any 0 | $16,000.62 | 21 total; 0 since its plan | |
| Saline city | City | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | $23,243.03 | 64 total; 32 since its plan | Includes $3,334.26 for declarations not counted as hazard incidents (EM-3189-MI). |
| Whitmore Lake CDP | Unincorporated | Expired on 2010-07-12 | no Public Assistance recorded | 18 total; 12 since its plan | No NFIP community ID on this jurisdiction's plan row. | |
| Ypsilanti city | City | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 1 | $43,586.81 | 55 total; 18 since its plan | Includes $9,430.48 for declarations not counted as hazard incidents (EM-3189-MI). |
| Ann Arbor charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 112 total; 64 since its plan | |
| Augusta charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Bridgewater township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 2 total; 2 since its plan | |
| Dexter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 49 total; 24 since its plan | |
| Freedom township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Lima township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 7 total; 6 since its plan | |
| Lodi township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Lyndon township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Manchester township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 36 total; 13 since its plan | |
| Northfield township | Township | Expired on 2010-07-12 | FMA RL 1, SRL 0; any 4 | $4,886.64 | 0 total; 0 since its plan | Includes $4,886.64 for declarations not counted as hazard incidents (EM-3189-MI). |
| Pittsfield charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | $141,295.74 | 13 total; 10 since its plan | Includes $138,638.34 for declarations not counted as hazard incidents (DR-4494-MI, EM-3189-MI). |
| Salem township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 25 total; 17 since its plan | |
| Saline township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 64 total; 32 since its plan | |
| Scio township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 11 total; 10 since its plan | |
| Sharon township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Superior charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| Sylvan township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 5 total; 4 since its plan | |
| Webster township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 0 total; 0 since its plan | |
| York charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | no Public Assistance recorded | 5 total; 4 since its plan | |
| Ypsilanti charter township | Township | Expired on 2010-07-12 | FMA RL 0, SRL 0; any 0 | $36,773.41 | 55 total; 18 since its plan | Includes $27,585.50 for declarations not counted as hazard incidents (DR-4494-MI). |
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 2005-07-13county-coded records, property plus crops, nominal dollars | Zone-level damage since planproperty plus crops, reported for the zone | Public Assistance since plannominal dollars; see note | Note |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Cold Wave | $89,377,869,217 | $117,380,975 | 372,064 | $33,880 | $65,489 | $10,597,390 | under 0.0001% | $1,325,000 | Storm Events damage since the plan includes 1 zone-level Frost/Freeze record ($1,300,000): outside NRI's Cold Wave definition. | ||
| Drought | n/a | $0 | n/a | n/a | $0 | n/a | agriculture exposure is 0 in NRI | ||||
| Earthquake | $156,864,702,510 | n/a | 372,258 | $1,039,259 | n/a | $231,873 | 0.000663% | ||||
| Hail | $89,377,883,384 | $117,380,975 | 372,064 | $1,383,782 | $46,546 | $49,830 | 0.00155% | $1,000,000 | |||
| Heat Wave | $89,377,869,217 | $117,380,975 | 372,064 | $25,466 | $1 | $2,873,304 | under 0.0001% | $0 | |||
| Hurricane | $89,268,813,598 | $115,110,046 | 371,636 | $69,014 | $3,840 | $461 | under 0.0001% | ||||
| Ice Storm | $89,377,647,391 | n/a | 372,062 | $1,111,180 | n/a | $53,821 | 0.00124% | $8,350,000 | |||
| Inland Flooding | $89,309,131,066 | $929,952 | 3,636 | $46,578,651 | $14,314 | $40,170 | n/a (see note) | $7,910,000 | no Public Assistance recorded (2 declarations) | 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 | $840,278,408 | n/a | 3,282 | $2,439 | n/a | $4,589 | 0.00029% | ||||
| Lightning | $89,377,883,384 | n/a | 372,064 | $113,334 | n/a | $1,178,641 | 0.000127% | $271,000 | |||
| Strong Wind | $89,377,883,384 | $117,380,975 | 372,064 | $4,568,086 | $40,688 | $1,518,153 | 0.00511% | $645,500 | $42,137,500 | Storm Events damage since the plan includes 18 zone-level High Wind records ($41,665,500) and 4 zone-level Strong Wind records ($472,000): NOAA non-thunderstorm wind types, outside NRI's Strong Wind definition. | |
| Tornado | $89,377,883,384 | $117,380,975 | 372,064 | $11,986,074 | $998 | $8,860,570 | 0.0134% | $13,395,000 | no Public Assistance recorded (2 declarations) | ||
| Wildfire | $29,227,451,435 | $38,683,755 | 114,393 | $34,939 | $6 | $3,255 | 0.00012% | ||||
| Winter Weather | $89,377,869,217 | $117,380,975 | 372,064 | $136,867 | $405 | $41,255 | 0.000153% | $6,000,000 |
Totals since 2005-07-13 (Storm Events through 2026-06-30): 428 county-coded records, 398 with a damage value recorded (including $0), $23,221,500; 87 zone-level records, 81 with a damage value recorded (including $0), $57,812,500 reported for the zone; Public Assistance: none recorded on the 2 counted declarations.
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 | 372,064 |
| Building value (total, not at risk) | $89,377,883,384 |
| Agriculture value (total, not at risk) | $117,380,975 |
| NRI risk rating (all hazards) | Relatively Moderate |
| Expected annual loss, buildings and agriculture, all hazards | $67,255,258 |
| 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) | $25,453,312 |
| 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) | 1 | Severe repetitive loss, FMA definition (44 CFR 77.2) | 1 |
| Repetitive loss, NFIP insurance definition | 10 | Severe repetitive loss, NFIP insurance definition | 1 |
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 | 1 | 1 | 10 | 1 | 10 | 0 | 5 |
| of which: Ann Arbor city | 0 | 1 | 4 | 1 | 4 | 0 | 1 |
| of which: Ypsilanti city | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| of which: Northfield township | 1 | 0 | 4 | 0 | 4 | 0 | 3 |
| of which: Unknown (community ID Unknown in FEMA data) | 0 | 0 | 1 | 0 | 1 | 0 | 0 |
| Statewide, no county in FEMA's file | 0 | 0 | 4 | 0 | 4 | 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 |
|---|---|---|---|---|---|---|---|---|
| Ann Arbor city | 260213 | 0 | 1 | 4 | 1 | 4 | 0 | 1 |
| Barton Hills village | 261154 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Chelsea city | 260599 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dexter city | 260600 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Manchester village | 260316 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Milan city | 260151 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Saline city | 260215 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ypsilanti city | 260216 | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| Ann Arbor charter township | 260535 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Augusta charter township | 260627 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Bridgewater township | 261786 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dexter township | 260536 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Freedom township | 261787 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Lima township | 261788 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Lodi township | 261789 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Lyndon township | 261790 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Manchester township | 261791 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Northfield township | 260635 | 1 | 0 | 4 | 0 | 4 | 0 | 3 |
| Pittsfield charter township | 260623 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Salem township | 260636 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Saline township | 261792 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Scio township | 260537 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Sharon township | 260538 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Superior charter township | 260540 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Sylvan township | 261793 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Webster township | 261785 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| York charter township | 260541 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ypsilanti charter township | 260542 | 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 | 1 | 0 | 7 | 0 | 7 | 0 | 5 |
| 2 to 4 unit residential | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| other residential | 0 | 0 | 1 | 0 | 1 | 0 | 0 |
| non-residential | 0 | 1 | 2 | 1 | 2 | 0 | 0 |
| 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 9 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, organized by the items of FEMA's Local Mitigation Plan Review Tool, Element B. Each section heading names the item its tables support; the plan and FEMA's review decide whether the 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). Washtenaw County, MI: risk-assessment baseline packet, release 2026-10 (data as of 2026-09-30; County FIPS 26161). Automated baseline. https://hazardplain.org/mi/26161/ 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
Hazard Plain release 2026-10. As of 2026-09-30; Storm Events data through 2026-06-30. Automated baseline.