PHOENIX -- A massive dust storm descended on the Phoenix area on Tuesday night, drastically reducing visibility and delaying flights as strong winds downed trees and caused power outages for thousands of residents.
The dust cloud that hit the valley had originated in an afternoon storm in the Tucson area before moving north across the desert, said National Weather Service meteorologist Paul Iniguez. Before bearing down on the Phoenix valley, radar data showed the storm's towering dust wall had reached as high as 8,000 to 10,000 feet, he said.
Once it neared the valley, the cloud had fallen to some 5,000 feet, according to the weather service. KSAZ-TV in Phoenix reported the storm appeared to be roughly 50 miles wide in some spots. It briefly blanketed the city's downtown at around nightfall.
"This was pretty significant," Iniguez told The Associated Press. "We heard from a lot of people who lived here for a number of storms and this was the worst they'd seen."
The storm was part of the Arizona monsoon season, which typically starts in mid-June and lasts through Sept. 30.
The National Weather Service says strong winds with gusts of more than 60 mph rapidly moved the dust cloud northwest through Phoenix and the surrounding cities of Avondale, Tempe and Scottsdale. More than a dozen communities in the area also were placed under a severe thunderstorm watch until 11 p.m.
Some 8,000 Salt River Project utility customers were left without power, KNXV-TV reported late Tuesday.
The Federal Aviation Administration said on its website that because of low visibility in the area, no Phoenix-bound flights were allowed to leave Las Vegas or Los Angeles airports until 9 p.m., and flights at the airport were grounded for about an hour.
(Copyright 2011 by The Associated Press. All Rights Reserved.)