Backcountry travelers could trigger loose snow sluffs and soft surface slabs in steep avalanche terrain at the mid and upper elevations. These slides could entrain significant amounts of snow in long, sustained couloirs. Be wary of this type of terrain along with slopes above cliff bands or terrain traps. While less likely, skiers and riders still have some potential to trigger large to very large persistent slab avalanches on a variety of aspects above 7,500 feet. Below 7,500 feet, any avalanche activity is expected to be limited to isolated terrain features.
The Tetons have received between 15 and 20 inches of light density snow since Thursday morning. Winds associated with this snowfall have been light, and slab development has been limited. In steep, higher elevation avalanche terrain, skiers and riders could trigger soft surface slabs with depths ranging from one to two feet.
While poor structure can be found in the Teton snowpack, basal weak layers that formed early in the season continue to round and are mostly stable. These low probability/high consequence avalanches are likely to range from two to five feet deep at the mid and upper elevations. Up there, skiers and riders could also trigger persistent slab avalanches failing on faceted layers that formed on the surface of the snowpack or faceted snow surrounding crusts. These persistent slabs in the upper portion of the snowpack are easier to trigger and could range in depth from one to three feet.
Expect mostly clear skies overnight before low level clouds once again develop. As the day progresses, thin, high clouds could move into the region in the afternoon. Temperature inversions will develop during the nighttime hours with mountain lows in the positive single digits and valley lows in the negative single digits. As the day progresses, temperatures at all elevations will climb into the mid to upper teens. Ridgetop winds will be light and variable.The general avalanche hazard is expected to be Moderate in the mountains on Monday. While skiers and riders might be able to trigger an isolated pocket of soft surface slab from the last storm cycle, the primary concern will continue to be large to very large persistent slab avalanches. In the Tetons, these slabs will be difficult to trigger, and would likely involve either faceted layers that formed on the surface of the snowpack or faceted snow surrounding crusts. Togwotee Pass has the worst structure of the three forecast zones, but the overlying slabs are also the smallest. There, failures could occur on faceted snow throughout the snowpack. The Southwest Trails forecast zone has the highest chance for human triggered persistent slab avalanches; the snowpack has poor structure similar to Togwotee Pass, and the overlying slabs are deeper.
