Avalanche Forecast

Issued: Jan 1st, 2018 4:58PM

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

Avalanche Canada jfloyer, Avalanche Canada

Warmer weather, denser slab, more likelihood of triggering an avalanche.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday: Cold air in the valleys, warmer air up high. An above freezing layer is expected from approximately 1900-2400 m. Some valley cloud is possible, clear at upper elevations. Light southwesterly winds.Wednesday: basically a repeat of Tuesday, possibly slightly warmer.Thursday: Cloud developing in the afternoon. Lower elevations becoming warmer, although the above freezing layer is expected to remain in place. Light southerly winds.

Avalanche Summary

Recent reports are of a few wind slab avalanches to size 1.5 and loose dry avalanches running in steep terrain. The character of avalanches is expected to change over the next few days, with slab avalanches becoming more likely as the upper snowpack starts to settle with warm temperatures. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

15-30cm of low density new snow has buried a recently formed layer of feathery surface hoar and/or sugary facets. A layer buried mid-December that consists of surface hoar, sun crust and/or sugary facets is now down approximately 30-50cm. This layer is most prevalent in sheltered locations at treeline and below. Until recently, the snow above both of these weak layers has been soft and unconsolidated. Forecast warmer temperatures are expected to make the upper snow more dense, which could increase the likelihood of triggering on these layers. A crust which was formed by rain in late November is another major feature in the snowpack and is down approximately 70-100cm at treeline elevations.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Warmer weather is expected to make the upper snow more dense, increasing the likelihood of triggering a weak layer buried 30-50 cm below the surface.
Buried surface hoar is more likely to be preserved in sheltered openings at and below tree line.Watch for signs of slab formation at lower elevations, such as whumphing or shooting cracks.Sluffs may trigger deeper instabilities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs
Recent shifting winds have been redistributing loose snow into wind slabs on a variety of aspects.
Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 2nd, 2018 2:00PM

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