A near-breach of the Muddy River in Nevada prompted the evacuation of about 190 people from the Moapa Band of Paiutes reservation as severe rainstorms pummeled the region and caused flash flooding throughout the Southwestern United States on September 8 and 9.
In Arizona, two people were killed when their vehicles were swept away in flash floods. The deadly rains were due to a confluence of storms and seasonal moisture, according to Weather.com.
The remnants of Hurricane Norbert, which never hit land but came close enough to boost the surf considerably off Baja California, dumped record rainfall on much of the desert Southwest, Weather.com reported. It began as a tropical storm on September 2 off western Mexico, turned into a hurricane and hovered about 150 miles west of Cabo San Lucas as it strengthened to a category 3, Weather.com said. From there its moisture combined with that of the regular U.S. rainy season out west and the remains of another tropical storm to dump record rainfall on several states.
“Norbert's moisture, in tandem with remnant moisture from ex-Tropical Storm Dolly and the residual moisture already in place from the North American Monsoon, combined to enhance rainfall in the Desert Southwest, well after Norbert reached its peak intensity,” Weather.com said. “Norbert brought flash flooding to several locations across southern California, southern Nevada, and Arizona on Sept. 7. Then, a cluster of thunderstorms with heavy rain parked over the Phoenix metro the following morning, wringing out the wettest calendar day on record, there.”
The Phoenix metro area was inundated in general, with 3.29 inches of rain recorded by the National Weather Service at the Phoenix airport, “by far the most precipitation ever received in one day in the city. The previous record was 2.91 inches in 1939,” the Associated Press reported. “Other Phoenix metro areas received staggering amounts of rain for the desert. Chandler recorded 5.63 inches, while Mesa had 4.41 inches.”
In Nevada the storms washed out a piece of Interstate 15, the main thoroughfare between Las Vegas and Salt Lake City, which can carry up to 20,000 vehicles daily, the Associated Press reported. The stretch of highway is closed as crews clean up the rubble. Rising waters made several roads impassable in Zion National Park, leading to its closure for a several hours on Tuesday September 9, AP said.
"We had rivers running through people's yards. But as far as property damage to homes themselves, I think we fared pretty well," Sherryl Patterson, administrator at the Moapa Band of Paiutes’ tribal office, told AP.
Phoenix received more than three inches of rain, or one month’s worth in a day, and in Moapa, Nevada, more than four inches of rain fell in two hours, according to AP. California’s rainfall was a little less dramatic, though more than two inches did fall in an hour in one town, according to the Riverside Press-Enterprise.
“This is a typical late summer, early fall thunderstorm that we get from time to time,” National Weather Service meteorologist Cynthia Palmer told the Press-Enterprise.
Several states were considering making emergency declarations.