High avalanche danger is expected to continue for another day due to new storm slabs, high freezing levels, and above freezing air trapped in the alpine.
Confidence
Poor - Freezing levels are uncertain
Weather Forecast
Expect a lot of variability in this region due to the warm air from the West-Northwest meeting the cold arctic air from the Rockies. The West and South should be very warm with moderate Westerly winds, and the North and East should stay cooler with light Northeast winds. Freezing levels will vary on Wednesday as the storm ends and warm air tries to push East. Mostly clear on Thursday with cooler (alpine temperatures around -10) and drier conditions. Friday mostly clear with light winds and no precipitation.
Avalanche Summary
Natural and skier triggered avalanches up to size 2.0 releasing down 30-50 cm in the new storm slab.
Snowpack Summary
There is a great deal of variability across the region. The West and South have received up to 60 cm of storm snow in the past 48 hours, quickly followed by high freezing levels and warm air up into the alpine. The North and East of the region have had 20-30 cm of cold dry new snow over the past 48 hours with light Northeast winds. This new slab may be sitting on a patchy layer of surface hoar that was buried near the end of December. Deeper in the snowpack there is a persistent weak layer of surface hoar and crust that is now down about 60 cm.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.