May 15, 2011
An upper level low pressure system moved over the Pacific Northwest. Moist and unstable conditions ahead of the low triggered widespread thunderstorms with heavy rainfall and isolated large hail. This combined with the abundant spring snow-pack and wet ground to cause flooding and flash flooding. As the upper low brought colder air. late season heavy snow ended the episode in the Blue Mountains. Snowfall amounts in inches included Milkshakes Snotel (9) and High Ridge Snotel (7).
Source: NOAA National Weather Service Storm Events Database (event 312521). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Grant County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.