Storm damage inside the Safeway at 9705 N. Thornydale Road.

Courtesy of Northwest Fire District

A monsoon storm pounded Tucson's northwest side, flooding a Safeway supermarket after two storm pipes on the roof burst.

The pipes, which routed water to drain spouts that poured into the parking lot, were dropping water into the attic space and flooding the grocery store, said Capt. Adam Goldberg, a Northwest Fire District spokesman.

Safeway, 9705 N. Thornydale Road, near West Linda Vista Boulevard was closed and may re-open Friday, said Goldberg.

Firefighters helped evacuate the supermarket Thursday at about 5:30 p.m., and moved the pipes on the roof so the storm water could drop into the parking lot, Goldberg said.

The storm, which developed on the Santa Catalina Mountains, moved to the northwest side and Tucson's far westside shortly before 5 p.m., said Jeff Davis, a meteorologist with the National Weather Service.

There was flash flooding in washes an the storm downed trees at the Foothills Mall, West Ina Road and Interstate 10 area, and the area of Linda Vista and Thornydale, authorities said.

Winds were in excess of 60 mph and the storm dumped up to 2 inches of rain in sections of the city, mostly the northwest and southeast sides, Davis said.

Power lines and traffic signal lights were also affected near Linda Vista and Thornydale Road, Goldberg said. A tree fell on three cars in the parking lot at  Northwest YMCA, 7700 N. Shannon Road, he said.

About 2 feet of water gathered at the underpass at West Orange Grove Road and Interstate 10 at about 5:30 p.m., Davis said.

There also were strong downpours on Tucson's far eastside and southeast side, Davis said.

Tucson Electric Power Co. crews restored power to most 1,100 customers affected by Thursday night. There were about 640 customers without power at 8 p.m., and crews worked through the night to restore electricity, said Joseph Barrios, a TEP spokesman.

More rain is expected Friday and heavy rains are in the forecast for the weekend, said Davis.