Yesterday a skier triggered an 18 inch deep soft slab avalanche on a southeast aspect in the starting zone of the Pavel Wolf slide path on KB Ridge. That slab failed on a sun crust. Dangerous deep slab avalanches are still a threat, especially for snowmobilers who climb steep slopes. Avalanches are unlikely at the lower elevations.
Dangerous deep slab avalanches with depths to five feet could still fail on a layer of weak faceted snow that formed in December. Failure continues to be a possibility in areas where that persistent weak layer is not as deeply buried and may require larger triggers like a snowmobile or a cornice failure. The consequences of triggering one of these deep hard slab avalanches would be severe.
Pockets of wind slab up to 18 inches in depth could be human triggered in isolated terrain features like cliff areas, steep chutes and steep wind-loaded avalanche starting zones.
After a brief lull overnight, snowfall intensity will increase in the morning hours and continue through the day. Overnight lows in the mountains will be in the mid-teens before rising to near 20 in the afternoon. Southerly to southwesterly ridgetop winds will increase to 25 to 35 miles per hour.The general avalanche hazard is expected to be Moderate above 7,500 feet on Friday. As new snow accumulates and ridgetop winds increase, the chance for skiers and riders to trigger newly developed wind slabs will be on the rise in steep, wind-loaded terrain near upper elevation ridgelines. These slabs could reach depths up to 18 inches by Friday evening. Monitor the weather and be willing to change your travel plans if conditions warrant. The chance lingers for backcountry travelers to trigger persistent deep slab avalanches up to five feet in depth in some areas. These dangerous slides are more likely to be triggered where faceted layers from December are less than three feet below the snow surface; large triggers, such as snowmobiles or cornice failures, are more likely to be able to impact these deeply buried layers. Below 7,500 feet, the snowpack is mostly stable and avalanches are unlikely.
