Jefferson County, WI
FEMA National Risk Index scores, disaster declarations & hazard data
Jefferson County has experienced 14 federally declared disasters since 1965, most recently Severe Storms, Tornadoes, And Flooding in 2026. Its overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Jefferson County's highest-rated hazards are hail, tornado, and cold wave, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Recorded storm events have increased 44% over the past five years compared to the prior five-year period. Community vulnerability is relatively low (13th percentile nationally), indicating stronger recovery capacity than most US counties.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Jefferson County has been designated in 14 declarations since 1965, covering 7 disaster types including severe storm (5), flood (3), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2026 | Flood | Severe Storms, Tornadoes, And Flooding |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2008 | Severe Storm | Severe Storms, Tornadoes, And Flooding |
| 2008 | Snowstorm | Record Snow And Near Record Snow |
| 2007 | Severe Storm | Severe Storms And Flooding |
| 2005 | Hurricane | Hurricane Katrina Evacuation |
| 2004 | Severe Storm | Severe Storms And Flooding |
| 1993 | Severe Storm | Severe Storms, Tornadoes & Flooding |
| 1991 | Severe Storm | Severe Storms & Hail |
Showing the 10 most recent of 14 total declarations since 1965.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Very Low | 39.9 | 0 | 0 | — |
| Inland Flooding | Relatively Moderate | 79.5 | 28 | 0 | $1.0M |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Very Low | 43.4 | — | — | — |
| Heat Wave | Relatively Low | 71.3 | 11 | 0 | — |
| Tornado | Relatively Moderate | 86.1 | 17 | 0 | $450K |
| Hurricane | Very Low | 14.4 | 0 | 0 | — |
| Hail | Relatively Moderate | 93.4 | 43 | 0 | $8K |
| Strong Wind | Relatively Moderate | 67 | 0 | 0 | — |
| Winter Weather | Relatively Low | 58.9 | 0 | 0 | — |
| Ice Storm | Relatively Low | 43.9 | — | — | — |
| Cold Wave | Relatively Moderate | 85.3 | — | — | — |
| Lightning | Relatively Moderate | 80.8 | 1 | 0 | $150K |
| Drought | Relatively Low | 37.6 | 0 | 0 | — |
| Landslide | Very Low | 58.1 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Jefferson County ranks in the 13th percentile (Very low) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 13th | Very low |
| Socioeconomic status | 11th | Very low |
| Household characteristics | 7th | Very low |
| Racial & ethnic minority status | 34th | Low |
| Housing type & transportation | 43rd | Low |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 22nd | Relatively Low |
| Risk to homes | 22nd | Relatively Low |
| Buildings in direct exposure zone | 36.1% | — |
NOAA tracked 100 weather events in this county over 2016–2025: 41 in 2016–20 vs 59 in 2021–25 (+44% — frequency increasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Jefferson County?
According to the FEMA National Risk Index, the highest-risk hazards in Jefferson County, Wisconsin are hail, tornado, and cold wave. The county's overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Has Jefferson County received federal disaster declarations?
Yes. Jefferson County has received 14 federal disaster declarations since 1965, including declarations in 2026. The most common disaster type on record is severe storm (5 declarations).
Has Jefferson County had any FEMA disaster declarations in 2024, 2025, or 2026?
Yes. Recent federal disaster declarations for Jefferson County include Severe Storms, Tornadoes, And Flooding (2026). See the declarations table above for the full history since 1965.
How does Jefferson County's natural hazard risk compare to nearby counties?
Among neighboring counties, Dane County, WI has the highest overall natural hazard risk (Relatively Moderate) and Washington County, WI has the lowest (Relatively Low). Jefferson County is rated Relatively Low overall.
How is Jefferson County's composite disaster risk index calculated?
Jefferson County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Jefferson County's composite score of 76 means its overall natural hazard risk is higher than 76% of US counties.