AP News in Brief at 5:58 a.m. EDT

July 6, 2011 6:01 AM ET

PHOENIX (AP) — 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.