The snowpack has been slow to improve since last week's storm. Human triggering is still a very real concern. The weak and shallow early-season snowpack produced widespread whumpfing for field teams today.
Weather Forecast
Wednesday will bring warmer temps with Alpine areas seeing a high of -5 celsius. Winds will remain light and westerly for the next few days. Very light precipitation is possible late Thursday and into Friday, but no significant accumulations are expected.
Avalanche Summary
Natural activity continued today in the Spray with slab avalanches up to size 2.5 on South and East Aspects in the Alpine. Smaller avalanches (up to size 1.5) up to 36 hours old were also observed at treeline today in steep open terrain on all aspects.
Snowpack Summary
Observed a large portion of the area today on monthly snow study flight. Lots of wind transport at Alpine and Treeline elevations due to moderate to strong winds out of the West. Wind slabs are prominent in all lee and cross-loaded terrain at higher elevations. Whumpfing was widespread in areas traveled today. Total snowpack depth varied from 70 to 120cm deep. Previous storm snow has now settled to an average of 65cm at 2200m. The November rain crust remains prominent about 20 to 30cm off the ground, and there is a layer of facets above the crust.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.