Steady snowfall and strong southerly to westerly winds continue to create dangerous avalanche conditions. At the mid and upper elevations, human-triggered slab avalanches are likely on steep wind-loaded slopes and loose snow avalanches could occur naturally. Increasing wind speeds throughout the day will form wind slabs at the mid and upper elevations and possibly small isolated pockets at the lower elevations. Over the past 3 days, the Tetons have received up to 30 inches of snow with 3 inches of water. Backcountry travelers should use caution today and be mindful of steep terrain, especially over terrain traps with the significant amount of loose snow that could move down the slope.
Strong winds today will increase the hazard by loading slopes and forming slabs that are most likely to be found at the upper elevations on leeward slopes and in large start zones. Although, gusty conditions today will likely form areas of slab on terrain features including many aspects and elevations. The slab depths could be 3 feet and if triggered, these avalanches will entrain the new snow.
Weak, faceted snow from the December 5 interface could still result in larger avalanches up to 4 feet in depth. The activity on this layer has been limited but the increased load over the past 3 days has added stress on these layers. These persistent slab avalanches could be triggered by the weight of a single person or the impact of a wind slab. Careful evaluation of the snowpack is essential for assessing this potential avalanche problem.
Periods of moderate snowfall are expected to occur tonight and Monday as snow showers pass through the area. Another 4-8 inches of snow is expected in favored terrain by tomorrow night. Temperatures are to remain cold with mountain highs in the single digits. Winds are to average in the twenties but could have gusts into the fifties, particularly during precipitation events. The general avalanche danger will remain Considerable above 9000 feet in the Tetons and above 8500 feet in the Togwotee and Southwest Trails areas. Sensitive wind slabs could be easily triggered in steep wind loaded areas to depths of three feet. A lesser chance exists to initiate larger and more dangerous slabs with depths to five feet. Between 7500 and 9000 feet in the Tetons, the danger will be Moderate where similar avalanche problems exist although slabs will be smaller and less sensitive. Below 7500 feet in the Tetons and 8500 feet in the other areas, the avalanche danger will be Low and avalanche activity is unlikely except for in isolated pockets.
