riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Washtenaw County Disaster Risk

Washtenaw County, Michigan

FEMA Risk Rating

Relatively Moderate

National Percentile

89th

of 3,144 counties

State Rank

#6

of 83 (1 = highest risk)

Flood Risk

90th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Moderate

Higher than 90% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Relatively Low

Higher than 44% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively High

Higher than 97% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 74% of US counties

Hurricane

Tropical cyclone and hurricane risk

Relatively Low

Higher than 48% of US counties

Risk Overview

About Natural Disaster Risk in Washtenaw County, Michigan

Washtenaw faces moderate disaster risk

With a composite risk score of 89.28, Washtenaw County sits significantly above Michigan's state average of 49.56, placing it in the relatively moderate risk category. This score reflects exposure to multiple natural hazard types that residents should understand and prepare for.

High-risk county in Michigan landscape

Washtenaw ranks among Michigan's riskier counties due to its 89.28 composite score—nearly double the state average. The county's position reflects concentrated vulnerability to flooding and tornado activity that distinguishes it from most other Michigan communities.

Washtenaw outpaces regional peers

Washtenaw's risk score of 89.28 substantially exceeds nearby Wexford County's 33.91, though it falls below Wayne County's 98.95. This places Washtenaw in a middle tier of risk compared to its Michigan neighbors, facing real but not extreme hazard exposure.

Tornadoes and floods dominate locally

Tornado risk scores highest at 96.85, making severe wind events a serious concern, while flood risk at 90.30 threatens low-lying areas and properties near water. Earthquake risk of 74.27 also exceeds state norms, though it remains secondary to wind and water hazards for most residents.

Comprehensive coverage protects your investment

Standard homeowners insurance doesn't cover flood or earthquake damage—Washtenaw residents need separate policies given their 90.30 flood score and 74.27 earthquake exposure. A tornado-ready home plan including safe rooms or shelters, combined with appropriate insurance, provides essential protection for this moderate-risk county.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Washtenaw County

Top Hazards by Exposure

  1. #1
    TornadoPrepare
    97th percentile
  2. #2
    FloodPrepare
    90th percentile
  3. #3
    EarthquakePrepare
    74th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Risk Advisory: Washtenaw County

Risk Verdict

Washtenaw County's overall risk score at the 89th percentile nationally signals meaningful exposure to multiple natural hazard types. Comprehensive household preparedness — including reviewing insurance, maintaining emergency supplies, and knowing evacuation routes — is strongly recommended.

Hazard Breakdown

Tornado risk is Washtenaw County's dominant natural hazard, ranked at the 97th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 90th percentile nationally. Additional tracked hazards include earthquake (74th percentile), hurricane (48th percentile), wildfire (44th percentile).

Preparedness Context

Washtenaw County ranks at the 97th percentile nationally for tornado exposure. Unlike many slow-onset hazards, tornadoes in Washtenaw County can reach full intensity in minutes; a pre-practiced household shelter plan matters far more than stockpiled supplies. Alongside tornado exposure, flood at the 90th percentile nationally means Washtenaw County households face multi-hazard severe-weather seasons that benefit from a single integrated emergency plan covering both threats. Washtenaw County county emergency management typically publishes annual severe-weather preparedness guides tailored to local tornado patterns; households benefit from reviewing these before storm season begins each spring.

Regional Context

Compared to other Michigan counties, Washtenaw County runs 39.7 composite risk points higher than the state mean — reflecting above-average hazard concentration in this area.

Is your household prepared for Washtenaw County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Washtenaw County, MI?
Washtenaw County has a FEMA National Risk Index rating of Relatively Moderate, placing it in the 89th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Washtenaw County?
Washtenaw County is evaluated for five major natural hazard types: tornado (97th percentile), flooding (90th percentile), earthquake (74th percentile), hurricane (48th percentile), wildfire (44th percentile). The highest-risk hazard is tornado at the 97th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Washtenaw County risk compare to the Michigan average?
Washtenaw County's composite risk percentile is 89th, compared to the Michigan state average of 50th percentile. The state's overall risk rating is Relatively Low. This means Washtenaw County faces higher natural disaster risk than the typical county in Michigan.
Is Washtenaw County at risk for tornado?
Yes, Washtenaw County's tornado risk is at the 97th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Washtenaw County is at the 90th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Why is Washtenaw County higher risk than average?
Washtenaw County's composite risk score of 89th percentile is above the Michigan state average of 50th percentile. This elevated risk is driven by tornado exposure (97th percentile), along with flooding and earthquake risk. Geographic location, terrain, climate patterns, and proximity to flood zones or fault lines all influence a county's risk profile.
By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Data Source

Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.

Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.