Jul 16, 2012
A nearly stationary upper level low pressure area parked near Brookings, Oregon brought abundant moisture across eastern Washington. This combined with daytime heating to produce a few severe thunderstorms and locally heavy rainfall. The heavy rainfall caused flash flooding and landslides in several areas. The upper level low moved north away from the area late on July 20.
Source: NOAA National Weather Service Storm Events Database (event 405392). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Walla Walla County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.