Searchers on snowmobiles rescued 21 persons yesterday, including an infant, who survived the crash-landing of a twin-engine commuter plane on a mountainside and spent the night in a blizzard. Authorities said one person, Mary Kay Hardin of Steamboat Springs, Colo., died in the accident.

The survivors were taken out from the crash site 10,000 feet up in the Colorado Rockies in snowmobiles through a foot of fresh snow, some riding inside and others wrapped in down sleeping bags and strapped to the outside of the tractor-like vehicles.

Rocky Mountain Airways Flight 217 had left the ski resort town of Steamboat Springs at 6:55 p.m. Monday on a scheduled 45-minute flight over the Continental Divide to Denver. Fifteen minutes later, the pilot radioed that he was having trouble with ice and was heading back to Steamboat Springs.

"All of a sudden we hit a little turbulence and ran right into the ground," said Vern Bell, one of the passengers.

The first rescue crew, following the signal from an emergency locator transmitter on snowmobiles, reached the crash site early yesterday morning.

The rescue center was in a campground 18 miles from Colorado Highway 14, the nearest paved road, and more than 50 miles from the nearest hospital. Winds gusting to 35 mph, heavy snow and temperatures in the teens slowed the movement of survivors to hospitals.