San Juan County, Washington Natural Disaster Risk
FEMA National Risk Index assessment · WA
Very LowComposite Risk Score
National percentile: 35th
San Juan County faces very low composite natural disaster risk (NRI Risk Index score 35.4, 35th national percentile), driven primarily by earthquake and landslide exposure. Expected annual loss across all 18 hazard types is $10M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
San Juan County carries a very low composite natural disaster risk, with a National Risk Index score of 35.4 out of 100 — placing it in the 35th 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.
Most of San Juan County's expected losses come from earthquake (ground shaking from sudden movement along geologic faults) at Low risk — $4M in expected annual loss and about 0.02 events per year; landslide (downhill movement of rock, soil, and debris on unstable slopes) at Very Low risk — $3K in expected annual loss and about 0.33 events per year; and winter weather (heavy snow, blizzards, and hazardous winter conditions) at Low risk — $79K in expected annual loss and about 4.79 events per year. Across all hazards, FEMA estimates $10M in expected annual loss for a population of 18K.
Beyond physical exposure, San Juan County has a high social vulnerability rating (how susceptible the population is to harm) and a very high community resilience rating (its capacity to prepare for and recover from disasters). Higher vulnerability is partly offset by strong community resilience and recovery capacity.
The county's disaster history tells the same story: San Juan County has received 12 federal disaster declarations since 1980, including 4 for flood events and 4 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides (flood), declared in January 2022.
Among 39 Washington counties, San Juan County ranks #33 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Earthquake | Low | 0.02 / yr | $4M |
| Landslide | Very Low | 0.33 / yr | $3K |
| Winter Weather | Low | 4.79 / yr | $79K |
| Coastal Flood | Low | 3.63 / yr | $354K |
| Riverine Flood | Low | 0.04 / yr | $5M |
| Wildfire | Very Low | 0.00 / yr | $25K |
| Volcanic Activity | Very Low | 0.00 / yr | $4 |
| Cold Wave | Low | 0.52 / yr | $398K |
| Ice Storm | Very Low | 0.04 / yr | $13K |
| Heat Wave | Very Low | 0.47 / yr | $28K |
| Tsunami | Very Low | 0.06 / yr | $31K |
| Lightning | Very Low | 4.28 / yr | $15K |
| Tornado | Very Low | 0.01 / yr | $13K |
| Hail | Very Low | 0.01 / yr | $808 |
| Strong Wind | Very Low | 0.00 / yr | $1K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 0.00 / yr | $0 |
| Hurricane | Very Low | 0.00 / yr | $0 |
Disaster History
San Juan County has received 12 federal disaster declarations since 1980, most recently Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in January 2022. Most frequent causes: Flood (4), Severe Storm (4), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| January 2022 | Flood | Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides |
| April 2020 | Flood | Severe Storms, Flooding, Landslides, and Mudslides |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| February 2007 | Severe Storm | Severe Winter Storm, Landslides, and Mudslides |
| May 2006 | Severe Storm | Severe Storms, Flooding, Tidal Surge, Landslides, and Mudslides |
| September 2005 | Coastal Storm | Hurricane Katrina Evacuation |
| November 2003 | Severe Storm | Severe Storms and Flooding |
| January 1997 | Severe Storm | Severe Winter Storms, Land & Muds Slides,Flooding |
| March 1991 | Flood | Severe Storms & High Tides |
Showing the 10 most recent of 12 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for San Juan County?
San Juan County has a composite FEMA National Risk Index score of 35.4 out of 100, placing it in the Very Low category and the 35th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in San Juan County?
The three highest-rated hazards are Earthquake (Low, $4M EAL), Landslide (Very Low, $3K EAL), Winter Weather (Low, $79K EAL). These account for most of the county's expected annual losses.
How does San Juan County compare to other Washington counties?
San Juan County ranks #33 of 39 Washington counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has San Juan County had?
FEMA records 12 federal disaster declarations for San Juan County since 1980, most often 4 for flood events and 4 for severe storm events. The most recent was Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared in January 2022.
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. San Juan County's $10M EAL is a statistical average, not a guarantee for any specific year or address.