Avalanche Forecast

Issued: Mar 16th, 2017 5:37PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada mbender, Avalanche Canada

Conditions vary throughout the region. Precipitation amounts and the freezing level have been higher overall from Valemount south. Ratings reflect conditions in the south of the region.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY: Scattered flurries / Moderate south wind / Alpine temperature -6 / Freezing level 1300mSATURDAY: Flurries, accumulation 10-15cm / Moderate to strong southwest wind / Alpine temperature -3 / Freezing level 1500mSUNDAY: Broken skies with isolated flurries / moderate to strong west wind / Alpine temperature -10 / Freezing level 800mMore details can be found on the Mountain Weather Forecast.

Avalanche Summary

There was a widespread natural avalanche cycle to size 3 on all aspects and elevations over the past 2 days in the areas south of Valemount. Although the natural avalanche cycle will have diminished, expect the recent storm slab to continue to be reactive at upper elevations.

Snowpack Summary

In the south of the region, surface snow up to 2000m has been moist or wet and with gradually cooling weather there may be a thin surface crust from between 1200 and 2000m. At upper elevations there has been 5-15cm of fresh snow with moderate to strong southerly winds each of the past several days creating storm slabs and wind slabs tree line and above. This recent new snow sits on faceted snow, thin sun crust on steep southerly aspects, as well as surface hoar in sheltered areas in some parts of the region. Approximately 80-120 cm below the surface you may find the mid-February persistent weakness. Professionals in the region have warned that the load above this layer has reached a critical amount, particularly where it presents as a crust. Deep persistent weaknesses in the lower third of the snowpack still have the potential to react to human triggers or smaller slab avalanches, especially with the warming air temperatures and/or intense sunshine.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm snow accumulations at upper elevations  over the previous 72 hours combined with moderate to strong southwest wind have created a touchy storm snow problem. Expect this to take a few days to settle and bond.
Be cautious as you transition into wind affected terrain.If triggered, the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Persistent weakness layered throughout the snowpack create the potential for very large step-down avalanches. The risk of triggering a deeper weak layer will be heightened while overlying storm slabs remain sensitive to human triggering.
Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.Avoid or use extreme caution around thin snowpack areas.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Mar 17th, 2017 2:00PM

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