A billowing wall of dust engulfed downtown Phoenix on Thursday, cutting visibility to a few hundred yards and delaying flights at the international airport, authorities and news reports said.

Driving rains and winds gusting at nearly 60 miles per hour also buffeted San Tan Valley, southeast of Phoenix in the early evening, according to the National Weather Service.

Roaring gusts downed trees and power lines in Pinal County, trapping drivers in their cars and preventing commuters from reaching their homes south of the state capital.

“This storm hit during a very busy time for traffic, bringing down power lines over several miles on top of cars with visibility near zero,” Pinal County Sheriff’s Office spokesman Elias Johnson said in a statement.