Mason County, Washington: Natural Disaster Risk and History
Mason County, Washington has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 85.3 out of 100, higher than about 85% of US counties, with landslides, earthquakes and inland (river and flash) flooding scoring highest of its 18 hazards and $44 million a year in expected losses.
OpenFEMA lists 30 federal disaster declarations that included Mason County since 1964, not counting 2 for COVID-19; the latest is DR-4906-WA (Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 7 April 2026). NOAA's Storm Prediction Center recorded 1 tornado touching Mason County from 1950 to 2025.
Live weather alerts for Washington All official warnings Latest FEMA declarations
Population 65,689 Buildings worth $14 billion Area 1,062 sq mi Risk rank in Washington 20 of 39 FIPS 53045
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Landslide | Relatively High | 98.1 | $500,180 | about 11 a year | — |
| Earthquake | Relatively Moderate | 97.2 | $26 million | about once every 34 years | — |
| Inland flooding | Relatively Moderate | 79.3 | $15 million | about once every 5.6 years | 5 |
| Coastal flooding | Relatively Moderate | 75.2 | $1.3 million | about 3.2 a year | — |
| Heat wave | Relatively Low | 68.0 | $653,467 | about 2.7 a year | 35 |
| Volcanic activity | Very Low | 48.2 | $8 | about once every 1,000 years | 1 |
| Winter weather | Relatively Low | 48.0 | $46,786 | about 12 a year | 209 |
| Wildfire | Very Low | 44.1 | $25,866 | rarer than once in 1,000 years | — |
| Tsunami | Very Low | 43.1 | $433,119 | about once every 18 years | 12 |
| Avalanche | Very Low | 41.4 | $225 | about once every 100 years | 0 |
| Ice storm | Very Low | 26.0 | $19,468 | about once every 3.3 years | 21 |
| Lightning | Very Low | 20.3 | $54,211 | about 5.2 a year | 12,162 strikes |
| Tornado | Very Low | 13.8 | $93,566 | about once every 23 years | 1 |
| Drought | Very Low | 12.6 | $5 | about 1.3 a year | 35 |
| Strong wind | Very Low | 6.3 | $33,390 | about once every 113 years | 1 |
| Hail | Very Low | 2.8 | $3,839 | about once every 97 years | 0.4 |
| Cold wave | No Rating | 0.0 | — | — | 0 |
| 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 30
Most common: Severe Storm 13, Flood 12, Earthquake 2, Fire 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 2 | Earthquake, Flood |
| 1970s | 3 | Flood ×3 |
| 1980s | 1 | Volcanic Eruption |
| 1990s | 5 | Severe Storm ×3, Flood ×2 |
| 2000s | 8 | Severe Storm ×5, Flood, Coastal Storm, Earthquake |
| 2010s | 4 | Severe Storm ×3, Flood |
| 2020s | 7 | Flood ×4, Severe Storm ×2, Fire |
The last 10
Widest declarations that included Mason 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 1
| Tornadoes touching the county | 1 |
|---|---|
| Strongest-rated | (E)F1 ×1 |
| Peak month | October (1) |
| Deadliest | — |
| Longest path | 18 Oct 2019, EF1, 0.7 mi path |
| Most recent | 18 Oct 2019, EF1, 0.7 mi path |
| Deaths / injuries on those paths | 0 / 0 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Mason County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Mason County (this page) | — | Relatively Moderate | 85.3 | Landslide |
| Grays Harbor County | 49 km | Relatively High | 97.0 | Tsunami |
| Kitsap County | 49 km | Relatively Moderate | 92.3 | Landslide |
| Jefferson County | 53 km | Relatively Low | 64.4 | Landslide |
| Thurston County | 56 km | Relatively High | 94.5 | Landslide |
| Pierce County | 91 km | Relatively High | 98.5 | Earthquake |
Nearest by distance between county centres. Every county in Washington, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively High 70.5 |
|---|---|
| Community resilience | Relatively Low 39.4 |
| Community risk factor | 1.33 |
| Expected annual loss, all hazards | $44 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 Mason County's main hazards
- Right now: National Weather Service alerts for Washington · all official warnings on Global Incident Tracker.
- Landslide: Landslides recorded
- Earthquake: Earthquakes today · Earthquake safety guide
- Inland flooding: Flood safety: why shallow water kills · Floods recorded
- 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 Mason County
What natural disasters is Mason County, Washington most at risk from?
Mason County, Washington has a Relatively Moderate natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 85.3 out of 100, higher than about 85% of US counties, with landslides, earthquakes and inland (river and flash) flooding scoring highest of its 18 hazards and $44 million a year in expected losses.
How many federal disaster declarations has Mason County had?
OpenFEMA lists 30 federal disaster declarations that included Mason County since 1964, not counting 2 for COVID-19; the latest is DR-4906-WA (Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 7 April 2026). Another 25 Washington declarations were made statewide without a county list.
How many tornadoes have hit Mason County?
NOAA's Storm Prediction Center recorded 1 tornado touching Mason 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.