Aug 18, 2021
An upper level trough and lead-on shortwave trough moved through Arizona during the day on the 18th. Moderate to high instability and high moisture content supported scattered strong thunderstorms. With deep south to southwest upslope flow, storms favored the foothills and mountainous areas of Maricopa and Gila counties. Most storms were producing at least 1 to 2 inch per hour rain rates, with several storms producing 2 to 3 inch rates and at times higher. Back-building and training of storms ov
Source: NOAA National Weather Service Storm Events Database (event 984220). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Maricopa County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.