Emergency crews from several agencies rescued one skier and were searching for at least two others after an avalanche of snow near Lone Peak in Utah on Thursday morning, the authorities said.

One person was rescued by helicopter and was being assessed by medical workers, while search-and-rescue crews were still looking for two others after reports of the avalanche near the peak, southeast of Salt Lake City, Sgt. Aymee Race, of the Unified Police Department of Greater Salt Lake, said.

Search-and-rescue teams were dispatched about 10:15 a.m., Sergeant Race said. The area was being surveyed by helicopter before determining whether search-and-rescue teams could move on foot, she said.

The avalanche had been reported in the backcountry, Benjamin Porter, a spokesman with the Unified Fire Authority, said.

It was unclear how much snow had fallen in the area.

This is a developing story and will be updated.