Two Montana snowmobilers and a cross-country skier have been killed in three separate avalanches. The body of the skier was recovered by Montana authorities just across the border in Wyoming after his wife reported he vanished in an avalanche as they skied together. Two hours earlier, a snowmobiler died nearby in southern Montana after he was buried for 12 minutes before his companions could dig him out. Another snowmobiler, 20 years old, triggered the slide that killed him, reports the Billings Gazette. Slopes in the area have been under a serious avalanche watch because of an unstable snow pack. Authorities recommend skiers and snowmobilers always travel with a partner and carry a shovel and an "avalanche transceiver" that emits a beacon so friends can locate those buried beneath the snow, reports KFBB-TV.