Avalanche Forecast

Archived

Dec 30th, 2016–Dec 31st, 2016

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis.

Some new snow has helped perk up the ski quality and valley bottom travel. Sheltered areas will be the place to be for the next while.

Confidence

High -

Weather Forecast

Mostly clear overnight with winds increasing at ridgeline. Tomorrow will see isolated flurries develop, but little accumulation. The alpine high will be -15. Winds will continue to increase, settling at 40-50km/hr from the west.

Avalanche Summary

-Numerous loose dry avalanches noted today on all alpine aspects. -Explosive control (Mt Rundle) produced a few sz 2's. Most of the avalanche volume came from entrainment of loose snow within the path.-A few slab avalanches noted at the base of cliffs in alpine terrain. Up to sz 2 and on east aspects.

Snowpack Summary

10-20 cm's of new snow fell last night. At treeline, the windslabs are now buried and somewhat disguised under the unsettled, new snow. Little wind today has done almost nothing for fresh storm slab development. The Dec 18 facet layer is now down 50cm on average. In the alpine, similar conditions exist due to the lack of significant wind. The only exception is in windward areas (westerly aspects) that saw intense wind scouring earlier in the week. Expect isolated(immediate lee) storm slabs and extensive windslabs on N to S aspects. The new snow is still low density with little cohesion.

Problems

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.

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.