San Juan County, Washington: Natural Disaster Risk and History
San Juan County, Washington has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 35.4 out of 100, higher than about 35% of US counties, with earthquakes, landslides and winter storms scoring highest of its 18 hazards and $9.9 million a year in expected losses.
OpenFEMA lists 10 federal disaster declarations that included San Juan County since 1980, not counting 2 for COVID-19; the latest is DR-4635-WA (Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 5 January 2022). NOAA's Storm Prediction Center has no tornado on record touching San Juan County from 1950 to 2025.
Live weather alerts for Washington All official warnings Latest FEMA declarations
Population 17,695 Buildings worth $6.8 billion Area 627 sq mi Risk rank in Washington 33 of 39 FIPS 53055
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Earthquake | Relatively Low | 89.4 | $4.3 million | about once every 52 years | — |
| Landslide | Very Low | 62.3 | $2,738 | about once every 3.0 years | — |
| Winter weather | Relatively Low | 60.0 | $79,066 | about 4.8 a year | 26 |
| Coastal flooding | Relatively Low | 58.4 | $354,246 | about 3.6 a year | — |
| Inland flooding | Relatively Low | 42.1 | $4.6 million | about once every 28 years | 1 |
| Wildfire | Very Low | 41.3 | $25,112 | rarer than once in 1,000 years | — |
| Volcanic activity | Very Low | 37.1 | $4 | rarer than once in 1,000 years | 1 |
| Cold wave | Relatively Low | 31.6 | $397,925 | about once every 1.9 years | 2.8 |
| Ice storm | Very Low | 19.1 | $13,317 | about once every 25 years | 2 |
| Heat wave | Very Low | 13.9 | $27,537 | about once every 2.1 years | 0.9 |
| Tsunami | Very Low | 6.2 | $31,349 | about once every 18 years | 12 |
| Lightning | Very Low | 5.5 | $15,377 | about 4.3 a year | 4,747 strikes |
| Tornado | Very Low | 4.4 | $13,121 | about once every 130 years | 0 |
| Strong wind | Very Low | 1.1 | $1,368 | about once every 301 years | 1 |
| Hail | Very Low | 1.1 | $808 | about once every 165 years | 0.4 |
| Drought | No Rating | 0.0 | — | — | 0 |
| Avalanche | Not Applicable | — | — | — | — |
| Hurricane | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 10
Most common: Flood 4, Severe Storm 4, Coastal Storm 1, Volcanic Eruption 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1980s | 1 | Volcanic Eruption |
| 1990s | 3 | Flood ×2, Severe Storm |
| 2000s | 4 | Severe Storm ×3, Coastal Storm |
| 2020s | 2 | Flood ×2 |
The last 10
Widest declarations that included San Juan County
- Hurricane Katrina Evacuation (2005, EM-3227-WA): 39 Washington counties designated.
- Volcanic Eruption, Mt. St. Helens (1980, DR-623-WA): 39 Washington counties designated.
- Severe Winter Storms, Land & Muds Slides,flooding (1997, DR-1159-WA): 38 Washington counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Washington also had 25 statewide declarations with no county list.
Tornado record since 1950 0
No tornado in NOAA's Storm Prediction Center record touched San Juan County between 1950 and 2025. That does not mean one cannot happen.
How San Juan County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| San Juan County (this page) | — | Very Low | 35.4 | Earthquake |
| Island County | 55 km | Relatively Low | 78.0 | Landslide |
| Skagit County | 92 km | Relatively Moderate | 88.8 | Volcanic activity |
| Clallam County | 93 km | Relatively Moderate | 89.7 | Earthquake |
| Whatcom County | 95 km | Relatively Moderate | 91.0 | Avalanche |
| Jefferson County | 104 km | Relatively Low | 64.4 | Landslide |
Nearest by distance between county centres. Every county in Washington, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively High 61.0 |
|---|---|
| Community resilience | Very High 95.8 |
| Community risk factor | 1.19 |
| Expected annual loss, all hazards | $9.9 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for San Juan County's main hazards
- Right now: National Weather Service alerts for Washington · all official warnings on Global Incident Tracker.
- Earthquake: Earthquakes today · Earthquake safety guide
- Landslide: Landslides recorded
- Winter weather: Power outages now · Carbon monoxide in winter
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about San Juan County
What natural disasters is San Juan County, Washington most at risk from?
San Juan County, Washington has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 35.4 out of 100, higher than about 35% of US counties, with earthquakes, landslides and winter storms scoring highest of its 18 hazards and $9.9 million a year in expected losses.
How many federal disaster declarations has San Juan County had?
OpenFEMA lists 10 federal disaster declarations that included San Juan County since 1980, not counting 2 for COVID-19; the latest is DR-4635-WA (Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 5 January 2022). Another 25 Washington declarations were made statewide without a county list.
How many tornadoes have hit San Juan County?
NOAA's Storm Prediction Center has no tornado on record touching San Juan County from 1950 to 2025.
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.