Brooklyn Gittins Missing: Volunteers Search For 13-year-old Utah Girl (VIDEO)

HERRIMAN, Utah -- Nearly 600 volunteers, dressed for the cold, showed up at a Mormon meetinghouse Thursday to help search for a 13-year-old Utah girl who disappeared without her shoes, coat or cellphone.

There were no signs of forced entry at the Herriman home where Brooklyn Gittins was last seen at bedtime Tuesday, said Unified Police Lt. Justin Hoyal.

"She has run away once before," Hoyal said, describing an incident four or five months ago. "But one of the big concerns is that she left without her stuff."

The possibility that she left the area in a car or bus has not been ruled out, but detectives have no indication of that. Authorities became concerned after they spoke with a list of friends given to them by the family and all of them said they didn't know where she was, Hoyal said.

Authorities were especially concerned because of an approaching cold front, with temperatures expected to stay below freezing for days. The National Weather Service is predicting 3-5 inches of snow in Herriman Thursday night.

Gittins - described as 5 feet tall and 115 pounds, with blond hair and blue eyes - was last seen wearing a T-shirt and black pajama pants with an image of a white Scottie dog, police said.

On Wednesday, a search helicopter and dog teams were dispatched, and police let residents know of the situation.

Police were dividing volunteers into teams to cover the area in a grid pattern Thursday. The 500 to 600 volunteers were broken into 50 teams. They've already canvassed the immediate area surrounding Gittins' house and were expanding the search area Thursday afternoon, Hoyal said.

Authorities will pull volunteers off the search once it gets dark or the snow storm hits, whatever comes first, he said.

Herriman is a Salt Lake City suburb located about 18 miles southwest of downtown.

Investigators were interviewing friends and acquaintances with the hope of learning more about the disappearance. They've received numerous tips about her whereabouts, but none has panned out.

"We're hoping for a good outcome," Hoyal said.

Salt Lake County Sheriff Jim Winder told the Deseret News that

The possibility that she left the area in a car or bus has not been ruled out, but detectives have no indication of that. Authorities became concerned after they spoke with a list of friends given to them by the family and all of them said they didn't know where she was, Hoyal said.

Authorities were especially concerned because of an approaching cold front, with temperatures expected to stay below freezing for days. The National Weather Service is predicting 3-5 inches of snow in Herriman Thursday night.

Gittins - described as 5 feet tall and 115 pounds, with blond hair and blue eyes - was last seen wearing a T-shirt and black pajama pants with an image of a white Scottie dog, police said.

On Wednesday, a search helicopter and dog teams were dispatched, and police let residents know of the situation.

Police were dividing volunteers into teams to cover the area in a grid pattern Thursday. The 500 to 600 volunteers were broken into 50 teams. They've already canvassed the immediate area surrounding Gittins' house and were expanding the search area Thursday afternoon, Hoyal said.

Authorities will pull volunteers off the search once it gets dark or the snow storm hits, whatever comes first, he said.

Herriman is a Salt Lake City suburb located about 18 miles southwest of downtown.

Investigators were interviewing friends and acquaintances with the hope of learning more about the disappearance. They've received numerous tips about her whereabouts, but none has panned out.

A tip line has been set up at 801-743-7280. Volunteers will deploy at 8 a.m. Thursday morning from The Church of Jesus Christ of Latter-day Saints stake center at 5562 W. 13680 South.