Yesterday, a skier jumped into a very steep, unsupported couloir and triggered a three foot deep hard slab. He was caught, carried over two cliff bands and partially buried. Luckily, he was uninjured and able to self-extricate. At the mid and upper elevations, similar slides could be triggered today in steep, wind-loaded avalanche terrain. The snowpack is mostly stable at the lower elevations and avalanches are unlikely. Moderate hazard is not a green light. Evaluate the terrain carefully, and come home to your friends and family this holiday season.
Earlier in the week, strong southwesterly to northwesterly winds created dense surface slabs on leeward aspects. These slabs could be triggered at the upper elevations and in isolated areas at the mid elevations with depths of one to three feet.
Snowfall will begin this evening, with the heaviest snowfall occurring between 9 PM tonight and 3 PM Christmas day as a cold front moves from the northern portion of the forecast area to the south. Strong southwesterly ridgetop winds will veer to the northeast as the front passes. As the day progresses, snowfall intensity will decrease and become lighter in density. Ten to 15 inches of new snow could accumulate by Thursday evening.The general avalanche hazard could increase to CONSIDERABLE on Christmas Day if forecasted snowfall amounts materialize. New surface slabs will develop overnight and into Thursday. Backcountry travelers could trigger these slabs in steep, wind-loaded starting zones above 7,500 feet. At the upper elevations, skiers and riders might be able to trigger persistent slabs up to three feet deep failing on surfaces from the early December dry spell.
