Park City, Utah ? An avalanche outside a Utah ski resort on Friday trapped at least three people beneath as much as 30 feet of snow, authorities said.

Summit County Sheriff Dave Edmunds said he did not know precisely how many people were missing in the slide, but said he was “willing to say more than two.” He did not know if victims were wearing avalanche beacons, which would transmit their locations.

No bodies had been recovered, and no survivors have been found in the avalanche, which was about 500 yards wide and happened outside the boundary of The Canyons resort on federal land in the Wasatch-Cache National Forest.

More than three hours after the avalanche, Edmunds said it was nearing time to change the focus of the operation from rescue to recovery.

Jess Fleig, a skier who spoke on a cell phone from a mountaintop while skiing at The Canyons, said he frequented the backcountry but stayed away from the popular Dutch Draw area Friday near where the slide took place.

“I looked at that ride probably 20 or 30 minutes before it went and what immediately came to mind is that’s trouble waiting to happen,” the 35-year-old disc jockey said. “It’s a very popular area. You have to hike 10 or 15 minutes to get there, but it’s marked with skull and crossbones and a warning that you could die.”

The Utah Avalanche Center warned of considerable avalanche danger Friday, which means human-triggered avalanches were probable.

A series of storms have dropped more than 6 feet of wet, heavy snow on the Wasatch mountains, setting up prime avalanche conditions.