A grass fire spread across an estimated 1,600 acres near the former Rocky Flats nuclear weapons plant Sunday amid wind gusts up to 50 mph, prompting officials to evacuate about 135 homes before flames were fully contained.

The fire was reported around 1:45 p.m. and was fully contained Sunday night, Jefferson County sheriff's office spokeswoman Jacki Kelley said.

Investigators determined the blaze was accidental. An electric pole in a field sparked the fire in high winds, Kelley said.

About 135 homes in the Walnut Creek subdivision were evacuated, and some 8,700 homes in the Countryside subdivision near Standley Lake in the northwest Denver suburb of Westminster were on alert, said Laura Koppel, a spokeswoman for the Westminster Fire Department. The evacuation order was lifted a few hours after the fire was reported.

Koppel said firefighters put some compressed air foam on some of the homes to protect them.

The fire quickly blackened hundreds of acres amid steady winds of 30 mph and gusts up to 50 mph.

Cindy Callahan, 41, and her husband, Pat, waited out the fire at a recreation center where evacuees were sent. She had gone shopping Sunday morning and heard from friends that the neighborhood might be evacuated.

"Our friends just grabbed our dog and the police didn't even let us in," she said.

Joseph Montgomery, 19, said his mother saw smoke near their house earlier in the day and called the fire department. They got the call to evacuate around 2:15 p.m.

"All I got was my wallet and shoes. I'm worried. Hopefully the firefighters can do what they can to prevent my house from catching on fire," he said before his family was allowed back home.

Residents as far as Arvada and Denver, roughly 15 miles southeast of Broomfield, could smell the smoke.