Jerome County, Idaho Natural Disaster Risk
FEMA National Risk Index assessment · ID
Very LowComposite Risk Score
National percentile: 21th
Jerome County faces very low composite natural disaster risk (NRI Risk Index score 21.5, 21th national percentile), driven primarily by wildfire and winter weather exposure. Expected annual loss across all 18 hazard types is $6M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Jerome County carries a very low composite natural disaster risk, with a National Risk Index score of 21.5 out of 100 — placing it in the 21st national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in wildfire (uncontrolled fires that spread across wildland and into communities) at Medium risk — $1M in expected annual loss and about 0.01 events per year; winter weather (heavy snow, blizzards, and hazardous winter conditions) at High risk — $228K in expected annual loss and about 9.79 events per year; and heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Low risk — $789K in expected annual loss and about 3.63 events per year. Across all hazards, FEMA estimates $6M in expected annual loss for a population of 24K.
Beyond physical exposure, Jerome County has a high social vulnerability rating (how susceptible the population is to harm) and a very low community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
History supports the rating: Jerome County has received 6 federal disaster declarations since 1964, including 2 for biological events and 2 for flood events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 44 Idaho counties, Jerome County ranks #31 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Wildfire | Medium | 0.01 / yr | $1M |
| Winter Weather | High | 9.79 / yr | $228K |
| Heat Wave | Low | 3.63 / yr | $789K |
| Earthquake | Very Low | 0.00 / yr | $319K |
| Volcanic Activity | Very Low | 0.00 / yr | $7 |
| Ice Storm | Low | 0.07 / yr | $34K |
| Avalanche | Very Low | 0.01 / yr | $120 |
| Riverine Flood | Very Low | 0.14 / yr | $3M |
| Cold Wave | Low | 0.21 / yr | $292K |
| Lightning | Low | 19.49 / yr | $77K |
| Drought | Very Low | 59.79 / yr | $8K |
| Strong Wind | Low | 0.43 / yr | $128K |
| Landslide | Very Low | 0.06 / yr | $22 |
| Tornado | Very Low | 0.05 / yr | $41K |
| Hail | Very Low | 0.26 / yr | $16K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Jerome County has received 6 federal disaster declarations since 1964, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Biological (2), Flood (2), Hurricane (1).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2017 | Flood | Severe Winter Storms and Flooding |
| September 2005 | Hurricane | Hurricane Katrina |
| September 2000 | Fire | Wildfires |
| December 1964 | Flood | Heavy Rains & Flooding |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Jerome County?
Jerome County has a composite FEMA National Risk Index score of 21.5 out of 100, placing it in the Very Low category and the 21th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Jerome County?
The three highest-rated hazards are Wildfire (Medium, $1M EAL), Winter Weather (High, $228K EAL), Heat Wave (Low, $789K EAL). These account for most of the county's expected annual losses.
How does Jerome County compare to other Idaho counties?
Jerome County ranks #31 of 44 Idaho counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Jerome County had?
FEMA records 6 federal disaster declarations for Jerome County since 1964, most often 2 for biological events and 2 for flood 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. Jerome County's $6M EAL is a statistical average, not a guarantee for any specific year or address.