Avalanche Forecast

Issued: Mar 13th, 2018 4:02PM

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

Avalanche Canada mgrist, Avalanche Canada

Isolated wind slabs at higher elevations are the main concern right now. Remain vigilant around cornices, and minimize overhead exposure.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

We're looking at small amounts of new snow and slightly warmer than normal temperatures throughout the forecast period. WEDNESDAY: Cloudy with some wet flurries in the afternoon (2-5 cm possible). Light to moderate south west winds. Freezing level falling to 1700 metres late in the day, with alpine high temperatures of +2.THURSDAY: Scattered flurries (2-5cm possible). Light northerly winds. Freezing level around 1700 metres with alpine high temperatures around 0 degrees.FRIDAY: Scattered flurries (2-5cm possible). Light north / east winds. Freezing level 1700 metres with alpine high temperatures of 0 degrees.

Avalanche Summary

Numerous wet loose avalanches were observed in the region to size 2.5 over the past four days, on sunny aspects. On Sunday we received reports of a skier caught in a size 2.5 avalanche in the north of the region. The slab was 20-50 cm thick and started on a steep north east aspect immediately below ridge crest at 2300m. See the MIN post for more details.

Snowpack Summary

The main story over the past several days has been the sun's effect on south and west facing slopes. Daytime heating has resulted in moist or wet snow on sunny aspects, freezing to form a crust overnight. A couple of layers buried in mid-late February (down around 40-100 cm) have shown limited reactivity of late. Persistent slabs have been triggered on shady aspects, where surface hoar and/or facets exist (see the Avalanche Summary above for more information).Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets also linger at the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
Snow and wind from last week have formed variable wind slabs. Slab avalanches may be triggered by solar radiation on solar slopes, by cornice fall, or with the weight of a person.
Use ridges or ribs to avoid pockets of wind loaded snow.Watch for wind loaded pockets near ridge crests and roll overs.Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 14th, 2018 2:00PM

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