Nov 12, 2021
An upper level trough Gulf Low continued off the west coast that brought a series of atmospheric rivers resulting in flooding across parts of western Washington. This second atmospheric river episode of the month was a set of three atmospheric rivers back-to-back-to-back. Water vapor transport into Western Washington averaged 160 - 200% of normal during the period of 11 November - 16 November. Heavy rainfall spread across the region on the night of the 11th through November 12, with the heaviest
Source: NOAA National Weather Service Storm Events Database (event 994114). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Snohomish County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.