New snow, wind and persistent weak layers in the snowpack will combine to create dangerous avalanche conditions. Well-developed persistent weak layers are present in the snowpack. These buried weak layers are variable in their distribution with respect to aspect, elevation and extent of development in specific avalanche paths. New snow and wind is increasing the load on those weak layers and increasing the hazard. Expert terrain and snowpack evaluation skills and restraint will be essential for safe travel in avalanche terrain. Natural and human triggered slab avalanches are likely on avalanche prone slopes. The additional snow will increase the size of this storm’s avalanche events and therefor increase the consequences of being caught.
Recent snowfall and winds have loaded weak layers of faceted snow that formed during a dry period that occurred earlier in December. Below this faceted snow, stout crusts from the end of November and sun crusts from December provide good sliding surfaces. Backcountry travelers could trigger slab avalanches failing on these layers to depths of one to three feet.
( Discussion is generated from the previous day's afternoon forecast. )Snow will return to the region as a stream of moisture moves across Oregon and northern Utah. Snow is expected to develop overnight and continue into Tuesday. Total storm accumulations of 8 to 17 inches are possible. Winds will be westerly at 20 to 25 with gusts from 35 to 40 miles per hour. Temperatures will be in the single digits and teens.The new snow and winds will be increasing the load on a snowpack with persistent weak layers that have very recently produced avalanches. Conditions will continue to be dangerous above an elevation of 7,500 feet. Natural and human triggered avalanches are likely on a variety of aspects and terrain features. Expert terrain and snowpack evaluation skills and restraint will be essential for safe travel in avalanche terrain. The additional snow will increase the size of this storm’s avalanche events and therefor increase the consequences of being caught. The general avalanche is expected to be CONSIDRABLE in the morning and may increase to HIGH.
