May 21, 2015
A large low pressure system off of southern California would spin up moisture to the area over several previous days. Embedded impulses would enhance convective activity leading up to the day. High CAPE and Perceptible Waters suggested thunderstorms with very heavy rainfall. Several areas across Yakima County WA recorded nearly an inch of rain in 30-60 minutes time. Enough dry air entrainment was available to produce a thunderstorm with a strong outflow boundary producing winds estimated t
Source: NOAA National Weather Service Storm Events Database (event 567335). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Yakima County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.