Jul 20, 2018
A southerly flow aloft brought some high level moisture into Central California on July 20. The moisture was sufficient enough for thunderstorms to develop over the higher elevations of the southern Sierra Nevada in the afternoon as the airmass became unstable with daytime heating. A few of the thunderstorms produced locally heavy rainfall over Yosemite National Park.
Source: NOAA National Weather Service Storm Events Database (event 759279). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Tuolumne County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.