PHOENIX -- The first dust storm of the summer rolled into the southeast part of the Valley on Friday afternoon.
The storm reached Phoenix around 2 p.m.
The Arizona Department of Transportation said gusts could hit speeds of 45 mph. A thunderstorm warning was in place for Pinal and Maricopa counties until 3 p.m.
Visibility could drop to as low as one-quarter of a mile.
The large dust storm is the first of the year to hit a major portion of the Valley. The massive clouds are normally associated with outflow winds from large monsoon storms.
Up to 1,000 SRP customers in the areas of Mesa and Queen Creek were without power because of the storm.
The monsoon season in Arizona began June 15 and runs through Sept. 30.
The Arizona Department of Transportation says motorists should avoid driving into dust storms in the first place by planning ahead and being prepared to change travel plans.
The driver-safety campaign advises motorists who find themselves in a dust storm to pull off the highway and park in a safe place off the pavement.
Other recommendations include turning off all lights, keeping your foot off the brake and staying in the vehicle while waiting for the storm to pass.
The Associated Press contributed to this report.