The snowpack has buried persistent weak layers that formed during dry periods earlier in the season. These slabs could be triggered by riders or skiers in steep avalanche starting zones above 8,000 feet. As the day progresses, shallow pockets of new wind slab will form on slick crusts and wind pack. The likelihood of triggering these new wind slabs will increase as the day progresses. Below 8,000 feet, the snowpack is mostly stable and avalanches are unlikely.
Buried layers of faceted snow persist in the snowpack. Skiers and riders could trigger slabs failing on these weak layers to depths of one to three feet. In the past six weeks, activity on these layers has only been observed on northerly through easterly to southerly aspects.
( Discussion is generated from the previous day's afternoon forecast. )The National Weather Service has issued a Winter Storm Warning for the Tetons and Gros Ventre Mountains beginning at 5 AM Sunday morning and continuing through 5 PM on Monday. During this same time period, the surrounding areas will be under a Winter Weather Advisory. Snowfall will develop overnight and continue through the day as moist, westerly flow resides over the region. Nighttime lows in the mountains will be in the teens before rising into the 20s during the day. Westerly ridgetop winds will range from 25 to 35 miles per hour with gusts to near 50.The general avalanche hazard is expected to increase to Moderate on Sunday. Wind slabs, which will form on stout sun crusts and wind pack, could be triggered by skiers and riders venturing in steep avalanche terrain. As the day progresses, these slabs will gain depth and volume. In the Togwotee Pass area, persistent weak layers deeper in the snowpack will remain a concern.
