Southwest flooding: more rains in store for Arizona, Utah

Monsoonal rains hit Arizona, Utah, Nevada, and Southern California Monday washing out roadways and carrying away cars. More rain is forecast.

The torrential rains that deluged the southwestern United States may not be over just yet. The National Weather Service is predicting “copious amounts of monsoon moisture” for Arizona and has issued a flood watch for southern Utah.

“The threat of flooding remains high due to heavily saturated soils and the anticipation of additional waves of precipitation,” Arizona Gov. Jan Brewer wrote in a declaration of emergency requesting $200,000 to begin addressing the damage of Monday’s rainstorms.

Arizona, Utah, Nevada, and Southern California all took a heavy pounding Monday as monsoonal moisture and the tail fringes of tropical storm Norbert converged. The storms washed out major highways, submerged cars and homes, and flooded intersections. At least two people drowned in floodwaters in Arizona.

A record 3.29 inches of rain fell on Phoenix Monday. Some areas reported as much as five inches of rain. The deluge rapidly flooded roadways and swept some cars a way.

Rescue crews in California received dozens of calls from motorists who had become stranded during their morning commute as strong thunderstorms pelted the desert, Riverside County fire spokeswoman Jody Hagemann said.

Flash flooding in Nevada washed out a large section of a major highway connecting Las Vegas to Salt Lake City forcing the closure of nearly 50 miles of Interstate 15. Transportation officials say it could take several days to reopen the highway.

“I don’t think it can be overstated just how important I-15 is to the three states,” Utah Department of Transportation spokesman John Gleason said.

Nevada rescue crews evacuated 190 people from the rural, native American community of Moapa about 50 miles northeast of Las Vegas, where incessant rains pushed the Virgin River to near-flood stage.

Monsoonal moisture is not uncommon for the late summer in the region, but in recent years, the patterns of precipitation have become erratic, meteorologist Charlotte Dewey said. The monsoon season is typically welcomed in the region as the area tends to be parched much of the year.

However, when too much rain falls too quickly, it can be difficult for the land to absorb the moisture. Instead of replenishing the soil, the rains end up washing directly into rivers and streams. This washing phenomenon is particularly common when the ground is unusually dry, as it has been in the Southwest throughout the past year.

The monsoon season can also bring thunderstorms, powerful downburst winds, and dust storms to the region.

Arizona’s Maricopa County experienced extensive flash flooding last month when 6.85 inches of rain fell on the small community of New River. 

This report includes material from the Associated Press and Reuters.