Avalanche Forecast

Moderate - Uncertainty is due to the track & intensity of the incoming weather system.

Tuesday Night: Snow, 5-10 cm, moderate to strong southwest wind, alpine high -5, freezing level 1300 m.

Wednesday: Flurries, 3-5 cm, moderate to strong southwest wind, alpine high -3, freezing level 1500 m.

Thursday: Cloudy with sunny breaks, moderate west wind, alpine high -8, freezing level 600 m.

Friday: Isolated flurries, light to moderate northwest wind, alpine high -7, freezing level 600 m.

There were no reports of avalanche activity on Monday or Tuesday. Expect to see an increase in wind slab activity in the wake of some new snow and strong winds arriving Tuesday night into Wednesday.

New snow accumulating Monday through Tuesday night has fallen on wind affected surfaces at upper elevations, surface hoar in wind sheltered areas and a thin crust on solar aspects. Winds are likely redistributing new snow into wind slabs and growing cornices. 

A few persistent weak layers exist in the upper to mid snowpack:

• The upper layer, found 40-60 cm down, is a spotty layer of surface hoar at treeline and below. 
• The lower layer, found 90-140 cm down, is widespread and can present as surface hoar and/or a crust.

Avalanche activity on these layers has dwindled since last week and snowpack tests results have generally indicated the weak layers are slowly gaining strength. Incoming snowfall in the forecast for this week will add additional load to these layers and may shed some light on whether they will remain a concern.

The lower snowpack is characterized by more crusts, the most notable is a rain crust from early November that is near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers in steep, shallow, rocky areas with a thin to thick snowpack.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Wind slabs are most reactive during their formation.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.