Walla Walla County, Washington Natural Disaster Risk
FEMA National Risk Index assessment · WA
LowComposite Risk Score
National percentile: 60th
Walla Walla County faces low composite natural disaster risk (NRI Risk Index score 60.4, 60th national percentile), driven primarily by earthquake and ice storm exposure. Expected annual loss across all 18 hazard types is $20M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Walla Walla County at low composite risk, with a National Risk Index score of 60.4 out of 100 — placing it in the 60th 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.
Most of Walla Walla County's expected losses come from earthquake (ground shaking from sudden movement along geologic faults) at Medium risk — $5M in expected annual loss and about 0.00 events per year; ice storm (freezing rain that coats surfaces in heavy, damaging ice) at High risk — $830K in expected annual loss and about 0.54 events per year; and wildfire (uncontrolled fires that spread across wildland and into communities) at Low risk — $570K in expected annual loss and about 0.00 events per year. Across all hazards, FEMA estimates $20M in expected annual loss for a population of 63K.
Beyond physical exposure, Walla Walla County has a medium social vulnerability rating (how susceptible the population is to harm) and a medium community resilience rating (its capacity to prepare for and recover from disasters). Both measures sit toward the lower end, indicating relatively modest population sensitivity.
The federal record bears this out: Walla Walla County has received 13 federal disaster declarations since 1964, including 4 for flood events and 2 for biological events. The most recent was Severe Storms, Flooding, Landslides, and Mudslides (flood), declared in April 2020.
Among 39 Washington counties, Walla Walla County ranks #27 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Earthquake | Medium | 0.00 / yr | $5M |
| Ice Storm | High | 0.54 / yr | $830K |
| Wildfire | Low | 0.00 / yr | $570K |
| Heat Wave | Medium | 7.18 / yr | $2M |
| Winter Weather | Medium | 9.17 / yr | $163K |
| Landslide | Low | 1.04 / yr | $5K |
| Riverine Flood | Low | 0.61 / yr | $10M |
| Cold Wave | Low | 0.39 / yr | $971K |
| Hail | Low | 0.32 / yr | $179K |
| Avalanche | Very Low | 0.01 / yr | $261 |
| Strong Wind | Low | 0.33 / yr | $330K |
| Lightning | Low | 10.48 / yr | $101K |
| Drought | Very Low | 22.54 / yr | $9K |
| Tornado | Very Low | 0.04 / yr | $84K |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Walla Walla County has received 13 federal disaster declarations since 1964, most recently Severe Storms, Flooding, Landslides, and Mudslides in April 2020. Most frequent causes: Flood (4), Biological (2), Fire (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2020 | Flood | Severe Storms, Flooding, Landslides, and Mudslides |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2017 | Flood | Severe Winter Storms, Flooding, Landslides, Mudslides |
| July 2015 | Fire | Blue Creek Fire |
| March 2009 | Severe Storm | Severe Winter Storm and Record and Near Record Snow |
| August 2006 | Fire | Columbia Fire Complex |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| March 2001 | Earthquake | Earthquake |
| January 1997 | Severe Storm | Severe Winter Storms, Land & Muds Slides,Flooding |
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 Walla Walla County?
Walla Walla County has a composite FEMA National Risk Index score of 60.4 out of 100, placing it in the Low category and the 60th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Walla Walla County?
The three highest-rated hazards are Earthquake (Medium, $5M EAL), Ice Storm (High, $830K EAL), Wildfire (Low, $570K EAL). These account for most of the county's expected annual losses.
How does Walla Walla County compare to other Washington counties?
Walla Walla County ranks #27 of 39 Washington counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Walla Walla County had?
FEMA records 13 federal disaster declarations for Walla Walla County since 1964, most often 4 for flood events and 2 for biological events. The most recent was Severe Storms, Flooding, Landslides, and Mudslides, 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. Walla Walla County's $20M EAL is a statistical average, not a guarantee for any specific year or address.