Weak layers of faceted snow persist in the snowpack. One is deeply buried and formed in early December. Large slab avalanches have recently been triggered on this layer in the Teton Range and in the Togwotee Pass area. Another is comprised of surface hoar that formed in mid-January and has also been responsible for recent avalanche activity. At the mid and upper elevations dense wind slab avalanches and deep persistent slabs could be triggered by backcountry users. Careful terrain and snowpack analysis and a comprehensive understanding of the snowpack structure and implications is warranted. Most avalanche fatalities occur during periods of moderate or considerable hazard. Avalanches are unlikely below an elevation of 7,500 feet.
At the mid and upper elevations surface slabs formed by strong west to southwest winds could be triggered by skiers or riders on steep avalanche prone slopes. These slabs are up to 30 inches deep.
Dangerous deep slab avalanches continue to be a hazard at the mid and upper elevations. These large slab avalanches could be triggered by the weight of a single person or by larger triggers like a snowmobile. These slabs could propagate long distances, have depths to four feet and could carry severe consequences to anyone involved.
The chance for snow at the higher elevations continues through tonight with favored areas seeing up to five inches of new snow. An inch or two is possible in the valleys. During the day, lingering snow showers could provide periods of light snowfall. Temperatures are to rise from near ten degrees to twenty in the afternoon. West winds are to have twenty to thirty miles per hour averages with the stronger winds during the night while snowfall chances are greatest.The general avalanche will remain Moderate above 7500 feet and Low below that elevation. Humans have the potential to trigger avalanches involving deeply buried weaknesses in the snow. Slab depths increase with elevation, with soft slabs with two foot depths at 7500 feet and hard slabs with up to five foot depths at high elevations. More than one person or larger triggers such as snow machines may be required to initiate one of these slides however, a single person could cause failure if a particularly weak point on a slope is impacted. A slight chance will also exist to trigger recently formed and possibly new pockets of soft wind slabs on loaded features near ridge lines and peaks.
