Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain.

Monday night: Cloudy with flurries bringing 10-20 cm of new snow. Strong southwest winds.

Tuesday: Cloudy with continuing flurries bringing 5-10 cm of new snow and new snow totals to 15-30 cm, increasing overnight. Moderate southwest winds. Alpine high temperatures around -4. 

Wednesday: Mainly cloudy with continuing flurries bringing 5-10 cm of new snow and 2-day snow totals to 30-50 cm, continuing overnight. Moderate southwest winds. Alpine high temperatures around -5.

Thursday: Mainly cloudy with isolated flurries and a trace of new snow. 3-day snow totals of 35-60 cm. Light to moderate west winds easing over the day. Alpine high temperatures around -14.

Reports from the weekend included several notable MIN reports from the Barkerville area, where shooting cracks, whumphing, and both natural and machine triggered storm slabs were observed failing on our most recent surface hoar layer. One of these reports included a large (apparently older) persistent slab release near a large glide crack. 

Reports from the interior of the region on Saturday included other observations of several recent small (size 1.5) natural wind slab releases. These occurred between 1800-2300 metres on steeper northeast aspects and featured crown depths of up to 40 cm.

A new layer of large surface hoar has been observed on the surface in sheltered areas of the region with a thin sun crust observed on many steep, sun exposed aspects. These surfaces are now being buried. 

Below the surface, 15-30 cm of recent snow has been either blown into soft wind slabs in alpine lees or remains low density. The interface below this snow may present as surface hoar on sheltered, shaded aspects, as a sun crust on steep sun-exposed aspects or as a more widespread melt-freeze crust below about 1700 metres. Reactivity at this layer has been noted in several recent MIN reports.

Below this interface, 60 to 120 cm of older storm snow is resting on a widespread layer of large, feathery, surface hoar from mid-December. This layer was a primary failure plane in the large natural avalanche cycle observed last week. Activity on this interface has tapered off, but there is concern for loading from forecast snowfall to reinvigorate avalanche activity at this depth.

A weak layer formed in late November is now buried around 1 m or more below the surface. Concern for this layer is limited to variable snowpack depth areas in the high alpine where it most likely exists as a combination of facets and crust.

• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Storm slab size and sensitivity to triggering will likely increase through the day.
• Be aware of the potential for large, destructive avalanches due to the presence of deeply buried weak layers.