Continued moderate snowfall have been steadily building storm slabs since 11/25.  Our thin “weak” snowpack will slowly adjust to this added weight. Natural and human triggered storm slab avalanches will be likely on 11/30, at mid and upper elevations.  Expect this hazard to increase as the next storm enters our area bringinging heavy precipitation and rising temperatures.

On 11/29 a full depth avalanche was observed at ~4000′ on a North aspect of Billy Mitchell. See avalanche activity section for more details.  Clouds have prevented further avalanche observations.  This indicates basal facets at the ground that are being overcome by increasing storm loads.  The distribution of basal facets in our area is unknown at this time.  This is a very dangerous problem since it will include the entire snowpack and it is very difficult to predict and manage.  This hazard is increasing with additional snowfall and rising temperatures forecasted.

Winds have been blowing from multiple directions since the last round of storms began 11/25.  With abundant dry snow available for transport, and changing wind direction expect wind slabs to have formed on a variety of aspects.  Avoid slopes that are actively, or have recently been loaded by wind.  Signs of recently loaded  slopes include: new snow that gets rapidly deeper over a short distance, like over a ridge or pass.  Pillowed snow surfaces, shooting cracks and freshly formed cornices.

Many Cornices are in their infancy stages of forming at this point in the season.  While traveling on or below cornices is always dangerous and never recommended. They can be especially dangerous early season when they may be made primarily of freshly drifted snow that almost surely can’t support the weight of a person or snowmachine.