Avalanche Forecast

Archived

Jan 2nd, 2017–Jan 3rd, 2017

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Jasper.

Ice-climbers need to be vigilant this week particularly if climbing in the Mt. Cirrus area. A couple of slabs were noted above the climbs but they did not crest the wall.

Weather Forecast

Temperatures and winds remain arctic like. Expect light N winds, no new snow, and clear skies for the next three days.

Snowpack Summary

Surface snow is facetting with the arctic temps and loosing internal cohesion. Southerly slopes in the alpine have been stripped by previous SW winds with hard slab on lee features. At treeline, the snow is faceted that is barely supportive and weak in shallow areas.

Avalanche Summary

Good visibility Jan 2 highway patrol. Several loose dry avalanches up to size 2 on steep alpine rocky terrain all aspects. 4 slabs up to size 2.5 noted on Mt. Cirrus above polar circus ice climb. They did not crest the wall but critical for ice climbers to take these into consideration. 1 icefall on Athabasca glacier did not initiate a slab below.

Confidence

The weather pattern is stable

Problems

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.