The PNW's flood seasonis now nine months long.
The Pacific Northwest used to count its flood threat in three storms a winter. Atmospheric rivers — the same phenomenon now defining California's flood map — have made the PNW one of the fastest-growing flood-loss regions in the country. The November 2021 atmospheric river that submerged Sumas and Abbotsford was a warning shot. The state of Washington has formally classified ARs as a separate hazard category.
Atmospheric rivers · River basin flooding · Coastal king tides
Sources: NOAA National Hurricane Center · NOAA NCEI Billion-Dollar Weather and Climate Disasters · National Weather Service. Figures reflect published agency totals; rounded where noted.
High-risk regions of the Pacific Northwest — and what's stored there.
Seattle / Puget Sound
Atmospheric river runoff plus king-tide coastal flooding. Heavy European exotic concentration on Mercer Island and Bainbridge.
Portland / Willamette Valley
Willamette and Columbia basin flooding. Concentration of restored American iron and pre-war vehicles in the West Hills.
Columbia River Gorge
Post-Eagle Creek fire debris flow plus AR runoff. Inherited family vehicles in Hood River and The Dalles.
Olympic Peninsula / Coast
Direct AR landfall zone. Weekend collector vehicles and restored American trucks.
Skagit & Whatcom Valleys
Nov 2021 ground zero. Dairy country with deep agricultural-vehicle restoration tradition.
Vancouver Island / Sunshine Coast
AR landfall plus king-tide coastal events. Cross-border PNW collections.
The Pacific Northwest AR protocol.
Forecast windows are shrinking. AR Cat 3 or higher: deploy.
- AR-5 dayWatch the NOAA AR scale. PNW ARs frequently arrive in 2- and 3-storm sequences.
- AR-3 dayPre-stage the vault. Confirm drainage and any post-fire watershed exposure.
- AR-1 dayDeploy before the first band. PNW AR rainfall is high-intensity and long-duration.
- AR-0Stay inside. Plan for sealed exposure of 48–96 hours per event.