Areas of unstable snow persist and serious avalanche accidents are possible. Large slab avalanches could be triggered on avalanche prone slopes by the weight of a single person or after a slope has been previously crossed by other skiers or riders. New snow and wind will be loading the snowpack and increasing the sensitivity of these persistent slabs to human triggers. Shallow pockets of new wind slab may begin to form on leeward aspects along the higher ridge crests. Collapses and shooting cracks are signs of instability. Expert terrain analyses skills, an understanding of our persistent slab avalanche problem and conservative terrain choices are essential for safe travel in avalanche terrain.
At the mid and upper elevations cohesive slabs sit upon a buried weak layer of faceted snow that lies atop a hard crust. This problem layer and bed surface can produce human triggered avalanches two to four feet deep on a variety of aspects, but has been most active on north through east to southeast aspects. Avalanches are unlikely below an elevation of 7,500 feet.
( Discussion is generated from the previous day's afternoon forecast. )Clouds will be on the increase as the southern branch of the jet stream directs subtropical moisture into the region. Some light snowfall is possible at the higher elevations overnight. Better chances for snow in the mountains will develop in the morning with heavier periods of snow likely in the afternoon and evening. New snow accumulations of 2 to 4 inches are possible at the higher elevation during the day. Another 4 to 8 inches are possible on Tuesday evening. The freezing level will fluctuate between 6,500 and 7,500 feet with rain showers possible below those elevations. Temperatures in the mountains will be the 20s and 30s. Winds will be southwest at 15 to 25 with gusts to 40 miles per.At the upper elevations new snow and strong winds will begin to form new wind slabs on leeward aspects. These slabs could grow to depths of 6 to 18 inches during the day. Concurrently at the mid and upper elevations the new snow will be increasing the load on a buried weak layer and therefor increasing the sensitivity of dangerous persistent slabs to human triggers. These slabs are two to four deep. Monitor the intensity and duration of the snowfall during the day and make good terrain selection choices. The general avalanche hazard is expected to be MODERATE in the morning and may increase to CONSIDERABLE during the day. Avalanches are unlikely at the lower elevations.
