Regions
Banff Yoho Kootenay.
The avalanche danger is reduced slightly from yesterday's peak of HIGH, but explosive triggered avalanches continue. Temperatures 5-10 degrees warmer were observed at higher elevations. Ice climbers should be wary of south facing overhead hazard.
Weather Forecast
The weather pattern will remain unchanged for the next few days. Only trace amounts of snow are expected, along with light to moderate westerly winds. Tuesday's temperatures will hit lows of -17, followed by gradual warming through the rest of the week. Big snow for next Saturday? We're too far out to have any confidence, but maybe.
Snowpack Summary
Total snowpack depths across the region range from 100-140 cm, and are comprised of soft surface snow above a weak and facetted snowpack. In many areas at treeline and above, recent winds have created thin windslabs. Foot penetration is to ground in most places, again demonstrating the weakness of the snowpack. This situation will not change soon.
Avalanche Summary
The widespread avalanche activity that was reported yesterday has subsided from its peak, although avalanche control today produced avalanches to size 2.5 in a number of locations. Most failures occurred at the ground level in the depth hoar, and human triggering is still likely in many locations.
Problems
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.
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.