Jul 28, 2021
A weak inverted trough moving across southwest Arizona and southeast California along with daytime heating resulted in the development of isolated thunderstorms over Joshua Tree National Park. High moisture levels in place allowed for these thunderstorms to be efficient rainfall producers, leading to locally high rainfall amounts. Officials with Joshua Tree National Park reported that running washes led to swiftly moving water flowing over several roads in the park. No injuries were reported.
Source: NOAA National Weather Service Storm Events Database (event 977079). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in San Bernardino County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.