The National Weather Service has issued a Winter Storm Warning effective from noon today through 5 PM on Sunday. Strong southwesterly to westerly ridgetop winds, new snow and ample snow available for transport have increased the depth and volume of wind slabs above 7,500 feet. Skiers and riders could trigger these slabs in steep, wind-loaded terrain. The increasing snow load will also raise the likelihood of triggering large to very large persistent deep slab avalanches. Safe travel will demand a conservative approach to terrain management. Monitor the weather, and be willing to turn around if conditions warrant. Below 7,500 feet, backcountry travelers might be able to trigger an isolated pocket of shallow wind slab on very steep, wind-loaded slopes.
Dangerous persistent deep slabs reside over faceted snow from December and January. Since Wednesday afternoon, around an inch of snow water equivalent has been added to the snowpack, and more is on the way. This increasing load will continue to raise the likelihood of triggering persistent deep slab avalanches that could range in depth from two to five feet.
Warmer temperatures and strong winds have created upside-down conditions, and skiers and riders are could trigger wind slabs on steep, wind-loaded slopes above 7,500 feet. As the day progresses, the likelihood of triggering these slabs will be on the increase, and depths could reach two feet by this evening.
( Discussion is generated from the previous day's afternoon forecast. )Light snow showers will linger overnight and into Saturday before northwesterly flow aloft brings a stronger system to the area later in the day. Overnight lows in the mountains will be in the single digits before climbing into the upper teens in the afternoon. Southwesterly to westerly ridgetop winds will range from 25 to 35 miles per hour with gusts to 50.The general avalanche hazard is expected to be CONSIDERABLE above 7,500 feet. In the morning, skiers and riders could trigger wind slabs ranging in depth from one to two feet in steep, wind-loaded terrain. With strong winds and new snow, the depth, volume and likelihood of triggering these slabs will all be on the rise as the day progresses, and natural activity will be possible. The increasing snow load will also raise the likelihood of triggering persistent deep slab avalanches. These dangerous slabs could exceed five feet in depth if failure occurs on faceted snow that formed during the December drought period. Safe travel will demand a conservative approach to terrain management on Saturday. Below 7,500 feet, backcountry travelers might be able to trigger an isolated pocket of shallow wind slab on very steep, wind-loaded slopes.
