Flash Flood — Maricopa, Arizona

2020-08-22 · near Tortilla Flat, Maricopa, Arizona

Event narrative

A strong thunderstorm produced heavy rain over southern portions of the Bush Fire burn scar during the evening of the 22nd. Heavy rainfall associated with the thunderstorm led to an estimated 1-2 of rain within 20-30 minutes over the headwaters of the Alder Creek basin, resulting in a flash flood with debris coming down Alder Creek. A group of people camping at the foot of Alder Creek on the north shore of Apache Lake attempted to flee the area by boat as the flash flood approached. The flash flood with debris caused an inoperable boat carrying five adults to capsize. Three out of the five adults were rescued out of the water by another boat. The other two adults, a 41 year old female and a 52 year old male, died as a result of drowning and were recovered by Maricopa County Sheriff's Office. Collaboration between the National Weather Service, Arizona Geological Survey, and Maricopa County Flood Control District determined that this event was not a debris flow.

Wider weather episode

A severe warned thunderstorm pushed west from southern Gila county into eastern Maricopa county in the late evening, after sunset. The storm produced very heavy rainfall over the southern end of the 2020 Bush fire burn scar in the Four Peaks Wilderness area. The rain led to flash flooding of Alder creek, which empties into Apache lake. The flash flood consisted of a lot of large debris and ash that led to a fatal boating accident on Apache Lake.

View location on OpenStreetMap → (33.5983, -111.3237)

Source: NOAA Storm Events Database, event_id 910149. Narrative written by the NWS forecast office that issued the report.