Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain on Thursday

TUESDAY NIGHT: Cloudy with clear periods. Freezing level dropping to valley bottom. Alpine temperatures around 0. Light southeast winds. WEDNESDAY: Mix of sun and cloud. Freezing level below 1600 m. Alpine high near 0. Light east-southeast winds. THURSDAY: Cloudy with isolated flurries, up to 5 cm. Freezing level at valley bottom, chance of inversion. Alpine high near -1. Light to moderate east-southeast winds.FRIDAY: Isolated flurries, up to 10 cm and snowfall continuing into Saturday. Freezing level 1400 m. Alpine high -1. Moderate south-southeast wind.More details can be found in the Mountain Weather Forecast.

Explosives triggered small cornices and one size 2 loose-wet avalanche in the alpine around mid-day Monday. On Sunday, two very large (size 3) slab avalanches were reported in the region. These avalanches occurred around 1500-1900 m and were observed on south-south east aspects. It is likely that that solar warming and sloughing triggered these avalanches Friday or Saturday. On Saturday, several large cornice falls were triggered naturally and with explosives. Some of these triggered size 2 slabs on slopes below. There is a trend of cornice falls increasing in size and frequency as the warm weather continues. Loose wet avalanches to size 2 were also failing naturally on sunny aspects on Saturday with continued reports into Sunday.

Warm temperatures can weaken surface snow layers and have recently made cornices touchy. The warmth can also penetrate into more deeply buried weak layers. Colder overnight temperatures are promoting better recovery of the snowpack, making for easier travel in the morning. Refrozen crusts may be found on all aspects below about 1800-2000 m; and on sunny aspects in the alpine. These may break down with warming through the day. Cold, dry and wind-affected snow may still be found on more north-facing and polar aspects in the alpine. Variable instabilities exist in recent storm snow layers. Two weak layers exist in the upper 2 m of the snowpack at and below treeline. These layers consist of surface hoar (feathery crystals) in more sheltered areas and a crust on solar aspects and on all aspects below 1600m.In the lower snowpack, a crust/facet (sugar snow) layer is now over 2 m deep. This layer may still be reactive to heavy loads (such as a cornice fall) in isolated areas.