New soft slabs are forming in the alpine and tree-line. Keep your eye attuned to changing danger levels with increasing winds and snowfall.
Weather Forecast
Rogers Pass seems to be stuck between the main flow of precipitation to the south and the cold air to the north. As a result, we will likely see light precipitation today, moderate WSW winds, and freezing levels rising to 1300m. This should continue into tomorrow.
Snowpack Summary
We had 20cm overnight. This buried settled snow on E and N aspects, and a sun crust on S and W aspects. Within the upper metre, several crusts are present, including the March 2 crust (down ~1m) which reacts with hard sudden results in tests. There is still large potential for propagation! The Feb10 layer is down ~2m, shallower in thin areas.
Avalanche Summary
Yesterday saw several solar-triggered loose natural avalanches in the highway corridor and in the backcountry to size 3.0. From Friday in Grizzly Bowl, east aspect, ~2600m, a size 3.5 avalanche slid, showing wide propagation from a large trigger (cornice).
Confidence
Track of incoming weather systems is uncertain
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.