Jefferson County, ID
FEMA National Risk Index scores, disaster declarations & hazard data
Jefferson County has experienced 6 federally declared disasters since 1976, most recently Covid-19 in 2020. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Jefferson County's highest-rated hazards are winter weather, cold wave, and earthquake, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Community vulnerability is relatively low (12th 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 6 declarations since 1976, covering 4 disaster types including biological (2), flood (2), hurricane (1).
| Year | Type | Event name |
|---|---|---|
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2017 | Flood | Severe Winter Storms And Flooding |
| 2005 | Hurricane | Hurricane Katrina |
| 1997 | Severe Storm | Severe Storms, Snowmelt, Land/Mud Slides, Flooding |
| 1976 | Flood | Dam Collapse, Flooding |
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 | 62.5 | 0 | 0 | — |
| Inland Flooding | Relatively Low | 37.1 | 7 | 0 | $3.1M |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Relatively Low | 80.6 | — | — | — |
| Heat Wave | Relatively Moderate | 79.1 | 0 | 0 | — |
| Tornado | Very Low | 7 | 2 | 0 | $10K |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Very Low | 20.6 | 7 | 0 | $9K |
| Strong Wind | Very Low | 12.4 | 0 | 0 | — |
| Winter Weather | Relatively Moderate | 82.7 | 0 | 0 | — |
| Ice Storm | Very Low | 10.9 | — | — | — |
| Cold Wave | Relatively Moderate | 81.8 | — | — | — |
| Lightning | Relatively Low | 54.7 | 1 | 0 | $1K |
| Drought | Very Low | 22.2 | 0 | 0 | — |
| Landslide | Very Low | 34.5 | 0 | 0 | — |
| Avalanche | Very Low | 1.9 | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Very Low | 58.3 | — | — | — |
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 12th 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 | 12th | Very low |
| Socioeconomic status | 17th | Very low |
| Household characteristics | 23rd | Very low |
| Racial & ethnic minority status | 41st | Low |
| Housing type & transportation | 10th | Very 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 | 78th | Relatively High |
| Risk to homes | 82nd | Very High |
| Buildings in direct exposure zone | 53.2% | — |
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, Idaho are winter weather, cold wave, and earthquake. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Jefferson County received federal disaster declarations?
Yes. Jefferson County has received 6 federal disaster declarations since 1976, including declarations in 2020. The most common disaster type on record is biological (2 declarations).
Has Jefferson County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Jefferson County since the start of 2024. Its most recent declaration on record is Covid-19 in 2020.
How does Jefferson County's natural hazard risk compare to nearby counties?
Among neighboring counties, Bonneville County, ID has the highest overall natural hazard risk (Relatively Moderate) and Clark County, ID has the lowest (Very Low). Jefferson County is rated Very 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 40 means its overall natural hazard risk is higher than 40% of US counties.