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Natural hazard risk in Washtenaw County, Michigan

Updated October 30, 2026. Based on FEMA, NOAA and OpenFEMA data. Published by Humblebee.

FEMA overall Risk Index rating: Relatively Moderate (score 89.2 of 100)[5]

Expected annual loss (FEMA)
$92.7 million[1]
Federal disaster declarations since 1965
9[2]
NFIP flood claims paid, 1978 to 2026
$1.6 million[3]
Tornadoes recorded, 1950 to 2024
28[4]

FEMA's National Risk Index rates overall natural hazard risk in Washtenaw County Relatively Moderate compared with other US counties[5]. The hazards with the highest FEMA scores in the county are strong wind, tornado and cold wave[6].

FEMA risk ratings for each hazard

Ratings and expected losses from the FEMA National Risk Index. Each rating compares this county with all US counties for that hazard, from Very Low to Very High. They are planning estimates, not predictions, and they do not describe any single property.

FEMA's National Risk Index (version 1.20, December 2025) gives Washtenaw County an overall Risk Index score of 89.2 out of 100, a score that compares the county with all US counties[5]. FEMA estimates Expected Annual Loss from all 18 natural hazards at $92.7 million a year[1]. By FEMA's estimates, the largest parts of that loss come from inland flooding, tornado and cold wave, in that order[7]. Expected Annual Loss is an estimate of average yearly loss and not a forecast of next year's damage[8]. FEMA rates social vulnerability Relatively Low, with a score of 21.4[9]. FEMA rates community resilience Very High, with a score of 97.0[10].

Hazards sorted by FEMA hazard-type Risk Index score, highest first
HazardFEMA risk ratingExpected annual loss
Strong WindRelatively High$6.1 million[11]
TornadoRelatively High$20.8 million[12]
Cold WaveRelatively High$10.7 million[13]
Ice StormRelatively High$1.2 million[14]
Inland FloodingRelatively Moderate$46.6 million[15]
LightningRelatively High$1.3 million[16]
Heat WaveRelatively Moderate$2.9 million[17]
HailRelatively Moderate$1.5 million[18]
EarthquakeRelatively Low$1.3 million[19]
Winter WeatherRelatively Moderate$179,000[20]
LandslideRelatively Low$7,028[21]
HurricaneVery Low$73,000[22]
WildfireVery Low$38,000[23]

Rated Not Applicable by FEMA for this county: avalanche, coastal flooding, tsunami, volcanic activity[24].

Social vulnerability and community resilience

FEMA uses these two ratings to scale expected losses into the Risk Index.

FEMA measureRatingScore
Social vulnerabilityRelatively Low21.4[9]
Community resilienceVery High97.0[10]

Flooding and flood insurance

FEMA rates inland flooding Relatively Moderate for Washtenaw County, with an Expected Annual Loss of $46.6 million a year[15]. OpenFEMA lists 416 residential flood insurance contracts in force as of 2026-08-03[25]. Inside FEMA's mapped Special Flood Hazard Area, 24.5% of homes are insured[25]. OpenFEMA data show 133 NFIP claims for losses from 1978 to 2026, and NFIP paid $1.6 million in total[3]. To learn about the flood zone for a specific address, use FEMA's Flood Map Service Center[26].

Measure Value
Inland Flooding, FEMA risk rating[15] Relatively Moderate, $46.6 million expected loss a year
NFIP residential flood policies in force (2026)[25] 416 of 111,497 homes
Homes in FEMA's mapped high-risk flood area (SFHA)[25] 799, of which 196 insured
NFIP flood claims, 1978 to 2026[3] 133 filed, $1.6 million paid

Is a specific address in a flood zone? Only FEMA's flood maps answer that, property by property[26]. This page describes the whole county.

Search an address on the FEMA Flood Map Service Center

Disaster declarations and tornado records

OpenFEMA lists 9 federal disaster declarations for natural hazards that include Washtenaw County since 1965[2]. The most recent, DR-4925-MI for severe storms, tornadoes and flooding, was declared 2026-06-30[27]. NOAA's tornado database records 28 tornadoes touching the county from 1950 to 2024[4]. The strongest were rated EF3[4].

Federal disaster declarations for natural hazards that include Washtenaw County, since 1965
Incident type Declarations
Snowstorm[2] 3
Flood[2] 2
Severe Storm[2] 2
Tornado[2] 1
Hurricane[2] 1
Most recent declarations
Declaration Incident Declared
DR-4925-MI[27] Severe Storms, Tornadoes, And Flooding 2026-06-30
DR-4607-MI[27] Severe Storms, Flooding, And Tornadoes 2021-07-15
EM-3225-MI[27] Hurricane Katrina Evacuation 2005-09-07
DR-1527-MI[27] Severe Storms, Tornadoes, And Flooding 2004-06-30
EM-3160-MI[27] Snow 2001-01-10

How to prepare

Steps from Ready.gov, FEMA's preparedness site, for the hazards with the highest FEMA ratings here. Follow instructions from local officials and the National Weather Service when a warning is issued.

Tornadoes

Before

  • Learn the warning signs: a rotating funnel cloud, an approaching cloud of debris or a loud roar like a freight train.
  • Sign up for community warning systems and learn what your local sirens sound like.
  • Pick a safe spot, such as a safe room built to FEMA criteria or an ICC 500 storm shelter, and practice getting there.
  • Include your pets in the household emergency plan.
  • Keep supplies, food, water and medication in case you have to stay home for a long time.

During

  • Go right away to the safe place you picked in advance.
  • Protect your head and neck with your arms and stay away from windows, doors and outside walls.
  • No place in a car is fully safe. If you can get lower than the road, leave the car and lie down there.

Source: Ready.gov, tornadoes

Winter storms and cold

Before

  • Insulate your home and learn how to keep pipes from freezing.
  • Install and test smoke and carbon monoxide detectors with battery backup.
  • Keep several days of supplies in case the power goes out, including medication and pet needs.
  • Put an emergency kit in your car with jumper cables, sand, blankets, water and snacks, and keep the tank full.

During

  • Under a winter storm warning, find shelter right away.
  • Stay off the roads if you can. If you are stuck in your car, stay inside it.
  • Run generators and grills only outdoors, away from windows, and never heat your home with an oven or stove.

Source: Ready.gov, winter storms and cold

Floods

Before

  • Check your flood risk with FEMA's Flood Map Service Center, and remember that floods do not follow map lines.
  • Sign up for your community's warning system. NOAA Weather Radio also broadcasts alerts.
  • Buy flood insurance through the NFIP well before a disaster. Homeowners policies do not cover flooding, and a new policy typically takes up to 30 days to go into effect.
  • Make a household plan with evacuation routes, shelter locations and what to do in a flash flood.
  • Keep important documents in a waterproof container and make password-protected digital copies.

During

  • If you are told to evacuate, leave right away and never drive around barricades.
  • Do not walk, swim or drive through floodwater. Six inches of moving water can knock you down.
  • If you are trapped in a building, go to the highest level, but do not climb into a closed attic.

Source: Ready.gov, floods

Questions people ask

Is Washtenaw County at risk of flooding?
FEMA rates inland flooding Relatively Moderate compared with other US counties, with an Expected Annual Loss of $46.6 million a year[15]. For a specific address, check FEMA's Flood Map Service Center[26].
Does Washtenaw County get tornadoes?
FEMA rates tornado risk Relatively High compared with other US counties[12]. NOAA's tornado database records 28 tornadoes touching the county from 1950 to 2024[4].
Is Washtenaw County at risk of earthquakes or wildfire?
FEMA rates earthquake risk Relatively Low[19] and wildfire risk Very Low compared with other US counties[23].
Is Washtenaw County at risk of hurricanes?
FEMA rates hurricane risk Very Low compared with other US counties[22].
How many disasters have been declared in Washtenaw County?
OpenFEMA lists 9 federal disaster declarations for natural hazards that include the county since 1965[2].

Facts and sources

  1. FEMA National Risk Index (version 1.20, December 2025): Expected Annual Loss from all 18 natural hazards in Washtenaw County is $92.7 million a year (Expected Annual Loss rating Relatively Moderate, score 90.1). Of this, buildings account for $67.1 million, injuries and deaths (converted to dollars by FEMA) for... FEMA National Risk Index
  2. OpenFEMA Disaster Declarations Summaries list 9 federal disaster declarations for natural hazards that include Washtenaw County since 1965 (5 major disaster, 4 emergency or fire management). By incident type: snowstorm 3, flood 2, severe storm 2, tornado 1, hurricane 1. Biological (such as COVID-19) and other... OpenFEMA Disaster Declarations
  3. HazardFacts tally of OpenFEMA NFIP Redacted Claims (losses from 1978 to 2026): 133 National Flood Insurance Program claims were filed for losses in Washtenaw County, 82 of them with a payment, and NFIP paid $1.6 million in total (building, contents and increased cost of compliance, in dollars of the year paid).... OpenFEMA NFIP claims
  4. NOAA Storm Prediction Center tornado database (1950 to 2024): 28 recorded tornadoes touched Washtenaw County. The strongest were rated EF3 (most recent of them on 2012-03-15). 4 were rated F3/EF3 or stronger. The most recent recorded tornado was on 2015-06-22. Ratings used the Fujita scale until early 2007 and the... NOAA Storm Prediction Center
  5. FEMA National Risk Index (version 1.20, December 2025): the overall natural hazard Risk Index rating for Washtenaw County is Relatively Moderate, with a Risk Index score of 89.2 out of 100. The score is the county's percentile rank among all US counties. FEMA National Risk Index
  6. Among the 18 hazards in the FEMA National Risk Index (version 1.20, December 2025), the hazards with the highest hazard-type Risk Index scores for Washtenaw County are strong wind (97.9, Relatively High), tornado (96.8, Relatively High), cold wave (93.0, Relatively High). HazardFacts sorted FEMA's published scores;... FEMA National Risk Index
  7. HazardFacts sorted FEMA's hazard-type Expected Annual Loss values for Washtenaw County (National Risk Index v1.20): the largest are inland flooding ($46.6 million a year), tornado ($20.8 million a year), cold wave ($10.7 million a year), out of $92.7 million a year from all 18 hazards. FEMA National Risk Index
  8. FEMA's National Risk Index FAQ (December 2025): Expected Annual Loss is FEMA's estimate of the average economic loss in dollars from natural hazards each year. The index is not meant to predict how much damage a community will have in the next year, and a hazard can still cause damage where a rating is low. Scores... FEMA National Risk Index documentation
  9. FEMA National Risk Index (version 1.20, December 2025): Social Vulnerability rating for Washtenaw County is Relatively Low (score 21.4). FEMA describes social vulnerability as how susceptible social groups are to the harm natural hazards cause. FEMA National Risk Index
  10. FEMA National Risk Index (version 1.20, December 2025): Community Resilience rating for Washtenaw County is Very High (score 97.0). FEMA describes community resilience as a community's ability to prepare for, withstand and recover from hazards. FEMA National Risk Index
  11. FEMA National Risk Index (version 1.20, December 2025), strong wind in Washtenaw County: Risk Index rating Relatively High (score 97.9 of 100). Expected Annual Loss $6.1 million a year (rating Relatively High). Annualized frequency 5.7 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  12. FEMA National Risk Index (version 1.20, December 2025), tornado in Washtenaw County: Risk Index rating Relatively High (score 96.8 of 100). Expected Annual Loss $20.8 million a year (rating Relatively High). Annualized frequency 0.35 events per year, from recorded occurrences over a period of record of 38 years. FEMA National Risk Index
  13. FEMA National Risk Index (version 1.20, December 2025), cold wave in Washtenaw County: Risk Index rating Relatively High (score 93.0 of 100). Expected Annual Loss $10.7 million a year (rating Relatively High). Annualized frequency 2.79 event-days per year, from recorded occurrences over a period of record of 18 years. FEMA National Risk Index
  14. FEMA National Risk Index (version 1.20, December 2025), ice storm in Washtenaw County: Risk Index rating Relatively High (score 90.3 of 100). Expected Annual Loss $1.2 million a year (rating Relatively High). Annualized frequency 1.78 event-days per year, from recorded occurrences over a period of record of 68 years. FEMA National Risk Index
  15. FEMA National Risk Index (version 1.20, December 2025), inland flooding in Washtenaw County: Risk Index rating Relatively Moderate (score 90.2 of 100). Expected Annual Loss $46.6 million a year (rating Relatively Moderate). Annualized frequency 1.18 event-days per year, from recorded occurrences over a period of... FEMA National Risk Index
  16. FEMA National Risk Index (version 1.20, December 2025), lightning in Washtenaw County: Risk Index rating Relatively High (score 88.7 of 100). Expected Annual Loss $1.3 million a year (rating Relatively High). Annualized frequency 36.85 events per year, from recorded occurrences over a period of record of 24 years. FEMA National Risk Index
  17. FEMA National Risk Index (version 1.20, December 2025), heat wave in Washtenaw County: Risk Index rating Relatively Moderate (score 87.4 of 100). Expected Annual Loss $2.9 million a year (rating Relatively Moderate). Annualized frequency 3.68 event-days per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  18. FEMA National Risk Index (version 1.20, December 2025), hail in Washtenaw County: Risk Index rating Relatively Moderate (score 85.8 of 100). Expected Annual Loss $1.5 million a year (rating Relatively Moderate). Annualized frequency 3.14 events per year, from recorded occurrences over a period of record of 37 years. FEMA National Risk Index
  19. FEMA National Risk Index (version 1.20, December 2025), earthquake in Washtenaw County: Risk Index rating Relatively Low (score 74.2 of 100). Expected Annual Loss $1.3 million a year (rating Relatively Low). FEMA's modeled annual frequency is 0.001 events per year. FEMA National Risk Index
  20. FEMA National Risk Index (version 1.20, December 2025), winter weather in Washtenaw County: Risk Index rating Relatively Moderate (score 73.0 of 100). Expected Annual Loss $179,000 a year (rating Relatively Moderate). Annualized frequency 10.47 events per year, from recorded occurrences over a period of record of... FEMA National Risk Index
  21. FEMA National Risk Index (version 1.20, December 2025), landslide in Washtenaw County: Risk Index rating Relatively Low (score 69.9 of 100). Expected Annual Loss $7,028 a year (rating Very Low). FEMA National Risk Index
  22. FEMA National Risk Index (version 1.20, December 2025), hurricane in Washtenaw County: Risk Index rating Very Low (score 48.3 of 100). Expected Annual Loss $73,000 a year (rating Very Low). Annualized frequency 0.01 events per year, from recorded occurrences over a period of record of 172 years for the Atlantic... FEMA National Risk Index
  23. FEMA National Risk Index (version 1.20, December 2025), wildfire in Washtenaw County: Risk Index rating Very Low (score 43.7 of 100). Expected Annual Loss $38,000 a year (rating Very Low). FEMA's modeled annual frequency is 0 events per year. FEMA National Risk Index
  24. FEMA National Risk Index (version 1.20, December 2025) rates these hazards Not Applicable for Washtenaw County: avalanche, coastal flooding, tsunami, volcanic activity. FEMA uses Not Applicable when its source data has no historical record of the hazard in the community and the hazard is not considered... FEMA National Risk Index documentation
  25. NFIP Residential Penetration Rates (OpenFEMA, as of 2026-08-03): 416 residential flood insurance contracts were in force in Washtenaw County, out of 111,497 residential structures, a penetration rate of 0.4%. Inside FEMA's mapped Special Flood Hazard Area there were 799 residential structures and 196 contracts, a... OpenFEMA NFIP penetration rates
  26. FEMA's Flood Map Service Center is the official public source for flood maps (Flood Insurance Rate Maps) produced under the National Flood Insurance Program. Flood zones apply to specific properties: look up an address there or ask the local floodplain manager. County-level ratings do not tell you the flood zone of... FEMA Flood Map Service Center
  27. Most recent federal disaster declarations for natural hazards (table on this page). OpenFEMA Disaster Declarations

FEMA's National Risk Index compares each county with all other US counties. Ratings are relative (Very Low to Very High), not a measure of safety. Never call a place safe, unsafe, good or bad to live in. Risk Index and Expected Annual Loss values are FEMA estimates for planning. They do not predict next year's losses and do not apply to a single property. Flood zones are set by FEMA flood maps for specific properties. County ratings and flood insurance counts do not tell anyone whether an address is in a flood zone. Disaster declaration, NFIP and tornado counts are records of the past for this county only. Do not compare with other counties unless a fact does.

Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties, v1.20 (December 2025). Retrieved from fema.maps.arcgis.com on October 30, 2026. This product uses the Federal Emergency Management Agency's National Risk Index dataset API or downloadable datasets 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). This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.