Record rainfall, water rescues in the Desert Southwest

The remnants of Tropical Storm Rosa have drenched the southwest corner of the United States.

The Phoenix metro area got hit the hardest. Frequent rain, torrential at times, fell from Sunday evening through Tuesday evening. Streets flooded, some schools closed, and at least one large sinkhole formed in the suburb of Avondale, according to a tweet from ABC 15.

Phoenix’s NBC affiliate, 12 News, reports that a man in nearby Scottsdale was rescued from knee-deep moving flood waters by the local fire department.

Tropical systems drop rain on the Desert Southwest every few years, but Rosa was a record breaker. According to the National Weather Service office in Phoenix, Tuesday was the wettest October day in the city’s history with 2.36” of rain at Phoenix International Airport. It became the eighth-wettest day overall on record, and so far this is the third-rainiest October in Phoenix with 2.68” through the first two days.

Senior meteorologist Jaret Rogers tells FreightWaves that around a dozen Flash Flood Warnings had been issued for the Phoenix metro area from Sunday evening through early Tuesday evening. Tropical systems can produce strong thunderstorms, too, but Rogers says the Phoenix office has not received wind damage reports from anywhere in its coverage region.

Paul Brown, a soil water expert and environmental scientist at the University of Arizona in Tucson, tells FreightWaves that the rain helped irrigate drought-stricken crops, but there’s a down side: it’s bad for cotton. Brown says the harvest, which typically peaks in October and November, will be delayed a couple weeks. The open cotton bolls will need extra time to dry out before they can be defoliated and processed. Brown also says the heavy, excessive rain can degrade the quality of the cotton.

Yuma wasn’t hit as hard with few reports of flooding. However, the airport recorded a daily record rainfall Tuesday of nearly 0.40”. This doesn’t sound like a lot, but for the desert it is. Even though the region has been in a severe drought for months, excessive rain can cause flash flooding there even in the absence of drought.

The number of street closings dwindles as the rain fades, and Phoenix will get a chance to dry out the next few days. According to the latest forecast the next best chance for more rain isn’t until Saturday night.