Walworth County, Wisconsin Natural Disaster Risk
FEMA National Risk Index assessment · WI
LowComposite Risk Score
National percentile: 75th
Walworth County faces low composite natural disaster risk (NRI Risk Index score 74.8, 75th national percentile), driven primarily by hail and tornado exposure. Expected annual loss across all 18 hazard types is $40M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Overall natural disaster risk in Walworth County is low, with a National Risk Index score of 74.8 out of 100 — placing it in the 75th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by hail (ice stones from severe thunderstorms that damage property and crops) at High risk — $3M in expected annual loss and about 4.40 events per year; tornado (violently rotating columns of air capable of catastrophic local damage) at Medium risk — $7M in expected annual loss and about 0.40 events per year; and cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $7M in expected annual loss and about 5.47 events per year. Across all hazards, FEMA estimates $40M in expected annual loss for a population of 106K.
Beyond physical exposure, Walworth County has a low social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
History supports the rating: Walworth County has received 13 federal disaster declarations since 1965, including 3 for snowstorm events and 3 for severe storm events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 72 Wisconsin counties, Walworth County ranks #20 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Hail | High | 4.40 / yr | $3M |
| Tornado | Medium | 0.40 / yr | $7M |
| Cold Wave | Medium | 5.47 / yr | $7M |
| Strong Wind | Medium | 5.29 / yr | $2M |
| Lightning | Medium | 37.60 / yr | $711K |
| Heat Wave | Low | 3.58 / yr | $1M |
| Riverine Flood | Medium | 0.93 / yr | $18M |
| Landslide | Low | 0.12 / yr | $5K |
| Winter Weather | Low | 14.16 / yr | $85K |
| Earthquake | Very Low | 0.00 / yr | $358K |
| Ice Storm | Low | 0.68 / yr | $78K |
| Drought | Low | 6.41 / yr | $109K |
| Wildfire | Very Low | 0.00 / yr | $13K |
| Hurricane | Very Low | 0.01 / yr | $3K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Walworth County has received 13 federal disaster declarations since 1965, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Snowstorm (3), Severe Storm (3), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2011 | Snowstorm | Severe Winter Storm and Snowstorm |
| June 2008 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| March 2008 | Snowstorm | Record Snow and Near Record Snow |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| June 2004 | Severe Storm | Severe Storms and Flooding |
| January 2001 | Snowstorm | Snow |
| June 2000 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| June 1976 | Drought | Drought |
Showing the 10 most recent of 13 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Walworth County?
Walworth County has a composite FEMA National Risk Index score of 74.8 out of 100, placing it in the Low category and the 75th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Walworth County?
The three highest-rated hazards are Hail (High, $3M EAL), Tornado (Medium, $7M EAL), Cold Wave (Medium, $7M EAL). These account for most of the county's expected annual losses.
How does Walworth County compare to other Wisconsin counties?
Walworth County ranks #20 of 72 Wisconsin counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Walworth County had?
FEMA records 13 federal disaster declarations for Walworth County since 1965, most often 3 for snowstorm events and 3 for severe storm events. The most recent was Covid-19 Pandemic, declared in April 2020.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Walworth County's $40M EAL is a statistical average, not a guarantee for any specific year or address.