Several buried weak layers in the middle and lower parts of the snowpack have become reactive again as they have been overloaded by recent snow and rain. Large avalanches are reaching historical run outs and crossing valley bottom trails.
Wind slabs over 1m deep exist at higher elevations and at ridge crests near tree line. These slabs are still reactive in tests and could produce avalanches. Cornices have also grown significantly and are fragile. Avoid areas with wind effect.
With warming temperatures we may start to see loose wet avalanches at lower elevations and on steep solar aspects over the next couple of days. Watch for clues like snowballing that indicate that the snow surface is warming.
Deep persistent slabs are best managed by:
Cornices are best managed by:
Southwest flow continues with flurries expected on Wednesday night, possible accumulations of 3-5 cm by Thursday. The temperatures will fall slightly on Thursday, but expect freezing levels to reach about 1500 meters with treeline temperature from -5 to -8. Winds will remain moderate from the southwest.
100cm of dense, rounded snow comprises the upper half of the snowpack and sits on a variety of different foundations depending on location. In shallow areas (eg: Field ice climbs) the base is weak depth hoar. In deeper areas (eg: Little Yoho Valley), the base is rounded and stronger. Shears persist in the deep facets, and within the storm snow.
Report of big avalanche activity on the Bow Hut approach today. Fresh size 2 avalanche over the trail, and a very large (estimated size 3.5) deep slab from the Vulture Glacier ran over the Bow Hut headwall and covered the trail through the moraines. These are our only reports from today, but they indicate that large avalanches remain very likely.