Avalanche Forecast

Issued: Dec 19th, 2018 4:43PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada kdevine, Avalanche Canada

Information from this area is limited, especially regarding recent avalanche activity. It is critical to supplement this forecast with your own observations. Back off if you see recent avalanches, experience whumphing, or see cracking in the snow.

Summary

Confidence

Low - Due to the number of field observations.

Weather Forecast

WEDNESDAY NIGHT: Cloudy with flurries, up to 5 cm, moderate southwest winds, alpine low temperature near -10°c. THURSDAY: cloudy with scattered flurries, up to 5 cm, northwest winds, 20-40 km/h, gusting to 60 km/h, alpine high temperature near -7°c. FRIDAY: Cloudy with sunny periods and isolated flurries, southwest winds, 25-40 km/h, gusting to 60 km/h, alpine high temperature near -8°c, low temperature near -11°c. SATURDAY: Cloudy with sunny periods and isolated flurries, southeast winds, 20-40 km/h, alpine high temperature near -9°c, low temperature near -11°c.

Avalanche Summary

On Sunday, recent slab avalanches, whumpfing, and cracking were observed in the Hankin area. See this MIN report. Natural slab avalanches were also reported last week during the start of the stormy weather, including two size 2 avalanches on east-facing wind-loaded slopes near treeline (1700m) and several smaller slabs in steep gullies at low elevations. See this MIN report from Ashman. Recent avalanches have likely failed in the storm snow and possibly on a weak layer from the early December dry spell found roughly 40-70 cm below the surface.

Snowpack Summary

A total of 40-70 cm of snow has fallen over the past week, likely forming storm slabs and wind slabs throughout the region. The combination of new snow and strong wind from the southwest is likely forming thicker and more sensitive wind deposits at higher elevations. The storm snow may still need a bit more time to form a good bond with the weak surface hoar (feathery crystals) and facets (sugary snow) that formed during the dry spell in early December. Information is very limited about the current strength of this potential weak layer. Deeper in the snowpack, there are several crusts including an early season crust with facets near the bottom of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
40-70 cm of new snow from the past week has the potential to form reactive slabs. Wind loaded slopes at higher elevations are the most suspect for human triggering.
Approach steep lee and cross-loaded slopes with caution.Be alert to conditions that change with elevation, aspect, and exposure to wind.Field observations have been limited. Supplement this forecast with your own observations.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 20th, 2018 2:00PM