Flash Flood — Maricopa, Arizona

2021-08-18 · near Carefree, Maricopa, Arizona

Event narrative

According to local media reports, the Maricopa County Sheriff's Office found two people had perished inside an ATV that was buried in mud and debris downstream in Camp Creek. MCSO was notified and began searching for the missing people around 1600MST on the 18th but did not recover the ATV until 0800MST on the 19th. Media reported that other recreationists were successfully rescued from the area, including a father and daughter who were trapped near Needle Rock Recreation Site and had to be rescued by helicopter. A Camp Creek rain gauge recorded 3.54 inches of rain between 1300MST and 1420MST. The Rackensack Canyon rain gauge measured 3.83 inches of rain between 1250MST and 1430MST. The Maricopa County Flood Control District also reported that Bartlett Dam Road was closed due to swiftly flowing water over the roadway from Camp Creek.

Wider weather episode

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 over the same areas resulted in significant to catastrophic flash flooding. A few burn scars experienced flash flooding, including the recent Telegraph burn area which had catastrophic flooding of the Russell Gulch drainage. There were also 2 fatalities on this day with off-roaders recreating near Camp Creek in northeast Maricopa County. The strong to severe storms also produced damaging winds from microbursts and small hail over lower desert locations.

View location on OpenStreetMap → (33.8471, -111.7922)

Source: NOAA Storm Events Database, event_id 983936. Narrative written by the NWS forecast office that issued the report.