Avalanche Forecast

Thursday night: Cloudy with isolated flurries and trace accumulations. Light northwest winds.

Friday: Cloudy with light flurries bringing a trace of new snow before increasing overnight. Light southwest winds, increasing overnight. Alpine high temperatures around -10.

Saturday: Cloudy with 15-20 cm of snow from overnight. Light northeast winds. Alpine high temperatures around -10.

Sunday: Increasing cloud. Light west winds, becoming moderate or strong at ridgetop. Alpine high temperatures around -11.

Reports from Wednesday included observations of numerous storm slabs triggering with ski cutting, primarily highlighting the north of the region. At 10-20 cm deep, these releases matched the depth of our most recent snowfall, but were also observed entraining snow to the depth of the crust buried up to 30 cm deeper.

Since the weekend storm, there have been a few reports of small storm and wind slabs from human triggers, in addition to several reported dry loose avalanches. 

During the weekend storm, numerous large (size 2-3) avalanches released naturally in the storm snow. These avalanches primarily occurred on leeward aspects at treeline and alpine elevations. A large cornice fall was reported Sunday on a north aspect at 2400 m, and it stepped down to a large slab avalanche.

With continuous stormy weather over the past week, there have been a handful of very large (size 3-4) avalanches breaking on deeply buried weak layers on slopes above 2000 m. Although the likelihood is decreasing in the aftermath of the storm, wind slab avalanches or large cornice fall may have the potential to step down to these layers.

30-50 cm of snow from the early part of the week now overlies older wind-affected snow at high elevations, with about half this amount instead overlying a widespread melt-freeze or rain crust to a variable upper extent of 1700-2400 metres in elevation. The recent snow has shown variable reactivity, with reports showing a mix of soft wind slabs around treeline, sluffing of low density snow in steep terrain, and poor bonding with the buried crust where it exists.

The mid and lower snowpack are generally well settled and strong. Although isolated, there are two deeper weak layers that may persist in some areas. A weak layer of surface hoar buried 90 to 170 cm deep may be found across the north of the region while a facet/crust layer from November may be found near the ground in shallower snowpack areas.

• Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
• Seek out sheltered terrain where new snow hasn't been wind-affected.
• Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.