A special warning has been issued for the substantial warming and sun this week. Extra caution is required around and below cornices, and on steep sun exposed slopes during the heat of the day.
Summary
Confidence
Moderate
Weather Forecast
The ridge of high pressure is expected to persist until Saturday morning. Thursday and Friday should be sunny with light alpine wind from the northwest and afternoon freezing levels above 3000m. Increasing cloud cover is expected on Saturday with moderate alpine wind from the southwest and freezing levels dropping below 2000m. Light scattered flurries are possible Saturday afternoon.
Avalanche Summary
On Tuesday, a skier triggered a small wind slab in steep rocky terrain on a west aspect at 2300m and went for a ride. A skier also triggered a size 2 storm slab on a north aspect at 1800m which was 20cm thick. Explosives triggered several cornices up to size 2.5 and no subsequent slabs were reported. Widespread natural sluffing was also reported up to size 2.5. On Monday, several size 1 skier triggered avalanches were reported. These were reported as the recent storm snow sliding over a melt-freeze crust. Natural sluffing was reported from solar aspects as well as one size 2 cornice release. On Thursday, continued warming, sun exposure, and limited overnight recovery means natural cornice releases and loose sluffing are expected to continue.
Snowpack Summary
A moist snow surface is reported to be widespread to mountaintops except for shaded true north aspects above 2000m. Warm overnight temperatures means there was a limited refreeze of the snow surface. A thin crust may have formed in some areas but is expected to quickly break down in the morning. Wind affected surfaces are reported in exposed alpine terrain in response to recently strong northerly winds. Large cornices are lingering and are expected to become very weak with the sustained warming this week. Below the snow surface, the mid snowpack is generally well-settled throughout with no notable persistent weaknesses.
