Warming this weekend will elevate the avalanche danger. Pay particular attention to sun affected slopes.
Summary
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
THURSDAY NIGHT: Dry, cooling overnight.FRIDAY: Dry with a mix of sun and cloud. Freezing levels rising to around 1500 m. Alpine temperatures around -2C. Light southerly winds.SATURDAY: Dry and sunny. Inverted conditions with an above freezing layer between 1800m and 2400m. Light southerly winds.SUNDAY: Dry and sunny. Inverted conditions with an above freezing layer between 1800m and 2400m. Light southwesterly winds.
Avalanche Summary
A size 3-3.5 persistent slab avalanche was skier triggered on the north side of the highway in Glacier National Park on Tuesday. This was triggered from a thin spot on the ridge at 2250 m on a south east aspect It ran to the valley bottom and is suspected to have run on a layer of surface hoar sitting on a crust that was buried in late November.
See the MIN post here. The onset of warmer weather may increase the likelihood of triggering a large avalanche.
Snowpack Summary
Although the recent new snow has now ended, wind slabs are likely still reactive in lee and cross-loaded terrain features at higher elevations. This new snow has fallen on widespread wind-affected snow at alpine and treeline elevations. Below this, the snowpack is generally well-settled. There is however, a layer of feathery surface hoar that is sitting on a crust that was buried late November down 100-200 cm. This crust is suspected to be the bed surface for few very large avalanches over the past several days on southwest through southeast aspects in this region.
jfloyer,
Avalanche Canada
