Thurston County, Washington Natural Disaster Risk
FEMA National Risk Index assessment · WA
HighComposite Risk Score
National percentile: 94th
Thurston County faces high composite natural disaster risk (NRI Risk Index score 94.5, 94th national percentile), driven primarily by landslide and earthquake exposure. Expected annual loss across all 18 hazard types is $191M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
Thurston County carries a high composite natural disaster risk, with a National Risk Index score of 94.5 out of 100 — placing it in the 94th national percentile and in the upper tier of natural-disaster risk nationally. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
The county's risk is driven primarily by landslide (downhill movement of rock, soil, and debris on unstable slopes) at High risk — $2M in expected annual loss and about 5.08 events per year; earthquake (ground shaking from sudden movement along geologic faults) at High risk — $134M in expected annual loss and about 0.03 events per year; and volcanic activity (eruptions producing ashfall, lava, and pyroclastic hazards) at Medium risk — $195K in expected annual loss and about 0.01 events per year. Across all hazards, FEMA estimates $191M in expected annual loss for a population of 294K.
Beyond physical exposure, Thurston County has a very low social vulnerability rating (how susceptible the population is to harm) and a high community resilience rating (its capacity to prepare for and recover from disasters). A less vulnerable population paired with strong resilience helps the community absorb and recover from events.
The federal record bears this out: Thurston County has received 30 federal disaster declarations since 1965, including 14 for flood events and 9 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides (flood), declared in April 2026.
Among 39 Washington counties, Thurston County ranks #5 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Landslide | High | 5.08 / yr | $2M |
| Earthquake | High | 0.03 / yr | $134M |
| Volcanic Activity | Medium | 0.01 / yr | $195K |
| Riverine Flood | Medium | 0.14 / yr | $50M |
| Heat Wave | Medium | 4.26 / yr | $4M |
| Ice Storm | Medium | 0.63 / yr | $210K |
| Coastal Flood | Low | 3.10 / yr | $479K |
| Wildfire | Very Low | 0.00 / yr | $84K |
| Winter Weather | Low | 6.10 / yr | $95K |
| Lightning | Low | 6.73 / yr | $129K |
| Strong Wind | Low | 0.01 / yr | $282K |
| Tornado | Very Low | 0.04 / yr | $431K |
| Tsunami | Very Low | 0.06 / yr | $91K |
| Drought | Very Low | 1.28 / yr | $107 |
| Hail | Very Low | 0.01 / yr | $21K |
| Avalanche | Very Low | 0.01 / yr | $3 |
| Cold Wave | Very Low | 0.00 / yr | $21 |
| Hurricane | Very Low | 0.00 / yr | $0 |
Disaster History
Thurston County has received 30 federal disaster declarations since 1965, most recently Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in April 2026. Most frequent causes: Flood (14), Severe Storm (9), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| April 2026 | Flood | Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| December 2025 | Flood | Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| March 2022 | Flood | Severe Winter Storms, Snowstorms, Straight-Line Winds, Flooding |
| September 2020 | Fire | Bordeaux Road Fire |
| April 2020 | Flood | Severe Storms, Flooding, Landslides, and Mudslides |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| March 2012 | Severe Storm | Severe Winter Storm, Flooding, Landslides, and Mudslides |
| March 2009 | Severe Storm | Severe Winter Storm and Record and Near Record Snow |
| January 2009 | Flood | Severe Winter Storm, Landslides, Mudslides, and Flooding |
Showing the 10 most recent of 30 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Thurston County?
Thurston County has a composite FEMA National Risk Index score of 94.5 out of 100, placing it in the High category and the 94th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Thurston County?
The three highest-rated hazards are Landslide (High, $2M EAL), Earthquake (High, $134M EAL), Volcanic Activity (Medium, $195K EAL). These account for most of the county's expected annual losses.
How does Thurston County compare to other Washington counties?
Thurston County ranks #5 of 39 Washington counties for overall natural disaster risk, with a high rating.
How many federally declared disasters has Thurston County had?
FEMA records 30 federal disaster declarations for Thurston County since 1965, most often 14 for flood events and 9 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared in April 2026.
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. Thurston County's $191M EAL is a statistical average, not a guarantee for any specific year or address.