Sep 17, 2020
An eastward-moving upper level trough and associated area of surface low pressure moved across northwest Oregon and southwest Washington September 17-18, resulting in fairly widespread showers and thunderstorms beginning late in the afternoon of the 17th through most of the day on the 18th. One severe thunderstorm developed southeast of Salem, OR during the overnight hours of Sept. 17-18, and moved northward across the eastern Willamette Valley and Cascade Foothills before eventually weakening
Source: NOAA National Weather Service Storm Events Database (event 922988). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Cowlitz County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.