Increasing snowfall intensity and strong southwesterly ridgetop winds will combine to form isolated pockets of shallow wind slab in leeward terrain above 9,000 feet. As the day progresses, the chance for backcountry travelers to trigger these slabs will slowly increase. In a few, steep avalanche paths above 9,000 feet, the chance may persist for skiers and riders to trigger hard slab avalanches failing on deep instabilities within the snowpack.
Weak layers of faceted snow are preserved in the snowpack. At the upper elevations, hard slab avalanches with depths to three feet could be triggered by snowmobilers on steep, avalanche-prone slopes.
( Discussion is generated from the previous day's afternoon forecast. )A Pacific low pressure system will bring new snow to the area after midnight. In the mountains, snowfall intensity will increase during the day as moist, westerly flow develops. A mix of rain and snow will be possible in the valleys in the afternoon. Overnight lows in the higher elevations will be in the low 20s before increasing to near 30 during the day. Westerly ridgetop winds will back to the southwest at 15 to 25 miles per hour.In the Tetons, the general avalanche hazard is expected to be LOW Sunday morning. As the day progresses, moderate to heavy snowfall will combine with strong ridgetop winds to build new soft slabs in leeward terrain, and the hazard will increase.In the Southwest Trails and Togwotee Pass forecast zones, similar new slabs will build. In addition, deep instabilities persist, and the hazard will remain MODERATE. Although failure of these deep weak layers is unlikely in most areas, there remains a slight chance to trigger deep hard slabs on steep, avalanche-prone slopes above 9,000 feet that have not seen significant traffic this season.
