North Columbia

Warming this weekend will elevate the avalanche danger. Pay particular attention to sun affected slopes.

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.

Moderate - Freezing levels are uncertain

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.

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.