Flash Flood — Imperial, California

2021-08-31 · near Palo Verde, Imperial, California

Event narrative

Very heavy rainfall occurred along SR 78 in northeast Imperial County with amounts estimated to be approaching 7 inches in some places. This resulted in considerable flooding along the highway. The California Highway Patrol reported that a vehicle was swept off SR 78 at Milpitas Wash before overturning in the wash. Both occupants perished in the flash flood.

Wider weather episode

A similar pattern existed on the 31st compared to the previous day with an upper level low in the eastern Pacific near the west coast of the Baja Peninsula promoting diffluent flow across southeast California. Better moisture existed on this day compared to the previous day, leading to a more enhanced flash flooding event. The most intense rainfall occurred in northeast Imperial County along SR 78, where nearly 7 inches of rain was estimated to have fallen within a 5 hour period. An unbridged crossing along SR 78 at Milpitas Wash became flooded with swiftly flowing water due to the heavy rainfall. A vehicle attempting to cross through the flooded portion of the highway was swept off the roadway before overturning in the wash. Both of the occupants perished in the flash flood. Strong to severe thunderstorms across the Imperial Valley led to damaging wind gusts that resulted in numerous downed power poles. According to the Imperial Irrigation District, extensive damage sustained to the power infrastructure on both the 30th and 31st would cost the district more than $8 million.

View location on OpenStreetMap → (33.2712, -114.7978)

Source: NOAA Storm Events Database, event_id 983877. Narrative written by the NWS forecast office that issued the report.