The snowpack is continuing to adjust to the extended period of loading that started at the beginning of the year, and avalanche conditions remain dangerous at the mid and upper elevations. Up there, skiers and riders could trigger small pockets of newly developed wind slab in steep, wind loaded terrain. Large to very large persistent deep slab avalanches remain a serious concern at all elevations, and involvement in one of these destructive slides could easily result in a fatality. Conservative terrain choices and expert snowpack evaluation skills will be required for safe travel in avalanche terrain.
Southwesterly to westerly ridgetop winds easily transported yesterday’s light density snow, and new winds slabs up to a foot deep formed on leeward slopes above 7,500 feet. Backcountry travelers could trigger these slabs with depths up to 12 inches in steep, wind loaded terrain.
Persistent weak layers of faceted snow that formed during the extended dry period towards the end of December, along with basal facets that developed prior to Thanksgiving, were the culprits in a substantial avalanche cycle earlier in the week. Above 7,500 feet, backcountry travelers could trigger persistent deep slab avalanches failing on these weak layers with slab depths ranging from 4 to 8 feet. Below 7,500 feet, slabs failing on faceted snow could vary in depth from 1 to 3 feet.
After the chance for a few light, scattered snow showers overnight, dry conditions and mostly sunny skies are in store for Sunday. Overnight lows in the mountains will be in the low teens before climbing into the mid-20s in the afternoon. Westerly ridgetop winds will range from 5 to 15 miles per hour.Avalanche conditions are still dangerous in the Teton and Southwest Trails forecast zones, and the general avalanche hazard is expected to remain Considerable above 7,500 feet. Skiers and riders could trigger recently developed wind slabs up to a foot deep in steep, wind loaded terrain at the mid and upper elevations. Triggering persistent deep slab avalanches is still possible. With slab depths ranging between 4 and 8 feet above 7,500 feet, these slides are likely unsurvivable. Below 7,500 feet, human triggered slab avalanches could fail on faceted snow and are likely to vary in depth from 1 to 3 feet.On Togwotee Pass, where the January snowfall is around half that of the other two forecast zones, the general avalanche hazard is expected to be Moderate. The combination of a drop in the hazard rating and blue skies could lead you to drop your guard. Don’t fall into this trap. While the likelihood of triggering persistent deep slab avalanches is slowly decreasing, the consequences remain the same. These avalanches are likely to range in depth from 3 to 5 feet above 8,500 feet and between 1 and 3 feet below 8,500 feet. Involvement in one of these slides could easily result in a fatality.Light winds, warming temperatures and clear skies could increase the hazard on sunlit aspects in all forecast zones. Monitor the impact of the sun as the day progresses, and transition to shaded terrain if snow surfaces start to become damp.
