Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Tuesday night: 5-15cm of new snow / Extreme westerly winds / Alpine temperatures of about -15Wednesday: 2-4cm of new snow / Strong westerly winds / Alpine temperatures of about -16Thursday: 2-4cm of new snow / Strong southerly winds / Alpine temperatures of about -8Friday: 3-8cm of new snow / Light and variable winds / Alpine temperatures of about -8

Some notable persistent slab avalanches were reported last week. This included natural activity on the western slopes of the Purcells (two size 2.5 avalanches on the February 3rd surface hoar and one size 3.5 avalanche on the November crust) and two large skier triggered avalanches near Golden (including a size 3 remotely-triggered avalanche on the mid-January interface). Triggering a persistent slab avalanche is currently a low probability - high consequence scenario that warrants a cautious approach to terrain. Looking forward, new snow and extreme winds on Tuesday night are expected to promote new wind slab activity at treeline and in the alpine.

By Wednesday morning, new snow and extreme winds are expected to have formed fresh wind slabs at treeline and in the alpine. About 20-40 cm below the surface you'll likely find the mid-February interface which is composed of a thick rain crust up to about 2000 m, sun crusts on steep solar aspects, and spotty surface hoar on shaded aspects. Several deeper weak layers remain a concern including the February 3rd surface hoar layer (40-80 cm deep) in the southern Purcells, and the mid-January surface hoar layer in the northern Purcells (about 100 cm deep). Basal facets may still be a reactive in shallow rocky start zones.