Cornices are large and looming. Give them a wide berth as their failure has the potential to trigger deep instabilities. Trigger ability increases with daytime heating and sun.
Weather Forecast
The weekend will have flurries, clouds intermixed with sun, diurnal fluctuation of cold nights and freezing level 1000m or higher by the afternoon, and calm to light North winds. Monday and later will have sunny conditions, freezing level 1500m or higher, and trending increasingly warmer each afternoon.
Snowpack Summary
The surface storm and wind slab have melded with the snowpack making a persistent slab in alpine and treeline locations on a variety of aspects. 90cm has fallen since March 13 and was moved around by variable winds since then. At treeline in south facing terrain, the snow rests on a suncrust 80 cm deep. The snowpack is generally supportive.
Avalanche Summary
A size 3 triggered by cornice failure in the afternoon heat, scrubbed to ground, 2m crown, and ran full path occurred yesterday in the Shangrila area. A helicopter flight Tuesday revealed a significant avalanche cycle occurred on N to NE alpine slopes to size 3 and on terrain as low as 25 degrees triggered by wind loading and sunny skies.
Confidence
Timing or intensity of solar radiation is uncertain
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.