Washington County, Idaho Natural Disaster Risk
FEMA National Risk Index assessment · ID
Very LowComposite Risk Score
National percentile: 30th
Washington County faces very low composite natural disaster risk (NRI Risk Index score 30.3, 30th national percentile), driven primarily by wildfire and avalanche exposure. Expected annual loss across all 18 hazard types is $7M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Washington County at very low composite risk, with a National Risk Index score of 30.3 out of 100 — placing it in the 30th 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 — $3M in expected annual loss and about 0.01 events per year; avalanche (fast-moving snow and debris sliding down steep mountain slopes) at Low risk — $8K in expected annual loss and about 0.03 events per year; and landslide (downhill movement of rock, soil, and debris on unstable slopes) at Low risk — $6K in expected annual loss and about 1.47 events per year. Across all hazards, FEMA estimates $7M in expected annual loss for a population of 10K.
Beyond physical exposure, Washington 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: Washington County has received 9 federal disaster declarations since 1964, including 3 for flood events and 2 for biological events. The most recent was Covid-19 Pandemic (biological), declared in April 2020.
Among 44 Idaho counties, Washington County ranks #27 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Wildfire | Medium | 0.01 / yr | $3M |
| Avalanche | Low | 0.03 / yr | $8K |
| Landslide | Low | 1.47 / yr | $6K |
| Earthquake | Very Low | 0.00 / yr | $253K |
| Winter Weather | Low | 15.46 / yr | $51K |
| Volcanic Activity | Very Low | 0.00 / yr | $5 |
| Heat Wave | Very Low | 3.11 / yr | $158K |
| Riverine Flood | Low | 0.61 / yr | $3M |
| Strong Wind | Low | 0.23 / yr | $151K |
| Hail | Very Low | 0.22 / yr | $50K |
| Lightning | Very Low | 20.35 / yr | $45K |
| Ice Storm | Very Low | 0.01 / yr | $8K |
| Drought | Very Low | 23.53 / yr | $237 |
| Cold Wave | Very Low | 0.03 / yr | $41K |
| Tornado | Very Low | 0.06 / yr | $18K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
Disaster History
Washington County has received 9 federal disaster declarations since 1964, most recently Covid-19 Pandemic in April 2020. Most frequent causes: Flood (3), Biological (2), Severe Storm (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2017 | Flood | Severe Winter Storms and Flooding |
| July 2010 | Severe Storm | Severe Storms and Flooding |
| September 2005 | Hurricane | Hurricane Katrina |
| January 1997 | Severe Storm | Severe Storms, Flooding, Mud and Landslides |
| May 1977 | Drought | Drought |
| January 1974 | Flood | Severe Storms, Snowmelt & Flooding |
| December 1964 | Flood | Heavy Rains & Flooding |
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Washington County?
Washington County has a composite FEMA National Risk Index score of 30.3 out of 100, placing it in the Very Low category and the 30th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Washington County?
The three highest-rated hazards are Wildfire (Medium, $3M EAL), Avalanche (Low, $8K EAL), Landslide (Low, $6K EAL). These account for most of the county's expected annual losses.
How does Washington County compare to other Idaho counties?
Washington County ranks #27 of 44 Idaho counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Washington County had?
FEMA records 9 federal disaster declarations for Washington County since 1964, most often 3 for flood events and 2 for biological 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. Washington County's $7M EAL is a statistical average, not a guarantee for any specific year or address.