Avalanche Forecast

Thursday night: Mainly cloudy with isolated flurries. Light to moderate west to northwest winds. Alpine low temperatures around -10, freezing level valley bottom.

Friday: Mainly cloudy with scattered flurries accumulating up to 5 cm. Moderate to strong southwest winds, approaching extreme at ridgetop. Alpine high temperatures around -3 C, freezing levels rising to 1600 m, possibly higher.

Saturday: Flurries accumulating 5-10 cm, with light rain below 1500 m. Moderate west to southwest winds. Alpine temperatures around -6 C, freezing levels dropping to valley bottom.

Sunday: Mix of sun and cloud with isolated flurries. Moderate west to southwest winds. Alpine temperatures around -5 C, freezing levels valley bottom.

Explosive control work produced windslab avalanches up to size 2 on Thursday. 

The chance of full depth avalanches has diminished since the very large deep persistent slab avalanche cycle in response to storms prior to Christmas, but they could still occur under one of the following scenarios: we get unusually high accumulations of new snow or wind-blown snow; or from human-triggering in a thin, rocky start zone.

Recent snow and moderate winds have formed wind slabs up to 20 cm deep in the alpine and treeline. A reasonably consolidated upper snowpack, much of which was laid down during 50-100 cm of snow that fell just before Christmas, overlies a weak base. The bottom 30-50 cm of the snowpack consists of weak facets and crusts. Large deep persistent slab avalanches were noted during and immediately after the pre-Christmas storm and could be re-awakened by subsequent snowfall events.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Extra caution for areas experiencing rapidly warming temperatures for the first time.
• Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
• Be aware of the potential for large avalanches due to the presence of a deep persistent slab.