Dust Storm — Imperial County Southeast, California

2023-09-01 · Imperial County Southeast, California

Event narrative

Photos showed visibility dropped below 1/4 mile in blowing dust and sand along I-8 with winds gusting to 40 to 50 mph behind a strong outflow boundary. The strong gusts and reduced visibilities lasted for over 1 hour. No accidents were reported.

Wider weather episode

A deep southerly fetch of rich moisture up from the Gulf of California led to scattered to widespread heavy rainfall in Imperial and eastern Riverside counties during the afternoon of the 1st. Moisture values were well above normal for the time of year with precipitable water values analyzed around 2.0-2.2 inches. A Flash Flood Watch was issued for much of the region. Favorable dynamic and orographic forcing helped lead to strong updrafts and training of storms over certain terrain areas. Radar estimated rain rates were up to around 2-3 inches per hour with locally higher rates over shorter periods. There was a RAWS station in eastern Imperial County that measured right around 3 inches in 1 hour. These high rain rates led to areas of high rainfall accumulation, with many areas seeing at least 1 inch of rain and isolated areas up to 3.5-4.5 inches, radar estimated. This resulted in numerous reports of considerable flash flooding around the region. The hardest hit was the town of Niland and immediate surrounding area. A few inches of rain fell east of Niland leading to a canal being overcome with water and silt. This exacerbated the flooding and several inches of water flowed through the town and surrounding areas. The major impacts led to an emergency proclamation by the County of Imperial. In addition to the road closures, there were several swift water rescues across Imperial and Riverside Counties, both by land and air. One of the air rescues was completed by the San Diego US Coast Guard. On top of all the flooding, the heavy mass loading and strong updrafts resulted in strong to severe downburst winds, which caused a couple semi truck rollovers, downed many power poles, and generated dense blowing dust.

Source: NOAA Storm Events Database, event_id 1141474. Narrative written by the NWS forecast office that issued the report.