Jul 20, 2021
An unstable southwesterly flow developed ahead of an approaching Pacific trough and brought strong to severe thunderstorms over a three day period. Surface based CAPE routinely exceeded 1000 j/kg as steep mid-level lapse rates above 8C/km were common. Dry sub-cloud layers helped produce strong thunderstorm wind gusts and effective shear well above 30 kts was enough for quarter size hail and larger. The peak in severe weather occurred on Wednesday July 21st as the main energy associated with the
Source: NOAA National Weather Service Storm Events Database (event 972305). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Teton County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.