The avalanche hazard will be increasing today, especially at the upper elevations. Strong west-southwest winds are forming new soft slabs on leeward aspects. These slabs will gain depth and volume as the day progresses. A Winter Storm Warning has been issued by the National Weather Service for the period from 5 PM tonight through 5 AM Tuesday morning. The Bridger-Teton National Forest Avalanche Center has issued an Avalanche Watch for the same period and is likely to upgrade that watch to an Avalanche Warning by 5 PM this evening.
Strong west to west-southwest winds are forming new soft slabs on leeward aspects. These surface slabs are forming upon good sliding surfaces, are likely to be easily triggered by the weight of a single person and could increase to depths of 12 to 18 inches by evening.
On steep, northerly aspects above 9,000 feet, some potential persists for humans to trigger hard slabs to the base of the snowpack with depths to four feet.
( Discussion is generated from the previous day's afternoon forecast. )A moist northwest flow will bring areas of light snowfall to the mountains overnight and into the morning hours. This snowfall will increase and become more widespread during the afternoon and evening hours. Several inches of accumulation are expected in the mountains overnight. Another three to six inches of new snow will accumulate in favored locations during the day with most of this snowfall occurring later in the day. In the mountains temperatures will be in the single digits overnight and rise into the teens and 20s during the day. Winds will be west-northwest at 15 to 20 with gusts to 30 miles per hour.At the upper elevations west-northwest winds will continue to form new soft slabs on leeward aspects. The slabs will slowly gain volume and depth overnight and during the morning hours and more rapidly build during the afternoon hours. These new slabs are expected to be increasingly sensitive to human triggers and build to depths of 12 to 18 inches in isolated areas by evening. The general avalanche hazard is expected to MODERATE at the upper elevations and LOW at the mid and lower elevations.
