Very Dangerous avalanche conditions exist. Heavy snowfall and strong winds have resulted in conditions where natural avalanches are likely and humans venturing into avalanche terrain are very likely to trigger slides. These avalanches could involve new wind slabs and be small to large in size or they could be very large, involving deeper persistent instabilities within the snowpack. Travel in avalanche terrain is not recommended today. Teton Pass is closed this morning. WYDOT was able to trigger small avalanches in Hoback Canyon early this morning and then triggered a large slide in Glory Bowl on Teton Pass.
Slab avalanches involving buried weak faceted snow laying over hard crusts formed in late November could be triggered with depths of two to five feet on a variety of aspects. These slabs could be triggered by a single person, release naturally, or release after the initiation of a wind slab. Consequences of being involved in such a slide are likely to be very severe.
Heavy snowfall since yesterday afternoon, recent snow since Tuesday, and strong winds that have varied from the south to northwest have formed and continue to load wind slabs on a variety of aspects. These slabs will be very sensitive to human triggers today and could have depths to over three feet. Once triggered these slabs could cause failure deeper in the snowpack.
Periods of light snow are possible tonight through Saturday morning. Total accumulations of one to four inches are expected. Winds are to be westerly with fifteen to twenty five mile per hour averages. Partial clearing is expected Saturday afternoon with mountain temperatures reaching the mid-twenties. The general avalanche hazard will be Considerable above 7500 feet and Moderate below that elevation. The lowing of the hazard rating is based only on the decreased likelihood of natural avalanche activity. Make no mistake, DANGEROUS avalanche conditions continue and a single person could trigger a wind loaded slab from this week’s snowfall to depths of three feet or deep persistent slabs to depths of five feet. Note that given the recent storm and greater slab depths, this problem involving faceted snow over hard November crusts is being adjusted from a persistent slab problem to a deep persistent slab problem. This situation demands a very conservative approach to terrain and any deviation from that practice could result in serious injury or death. . Below 7500 feet the hazard is moderate where very weak snow could produce avalanche in steep north facing terrain above 7000 feet. Travel thru low elevation terrain should also consider exposure to the possibility of very large avalanches occurring in higher terrain.
