Significant storm expected to arrive by mid-day Tuesday with steady snowfall and increased winds.
Weather Forecast
5cm in the next couple of days. Significant storm expected to move in by mid-day Tuesday bringing as much as 50cm to the Columbia Icefields area. Winds expected to increase on Wednesday, with good potential for a reverse loading pattern. Temps to remain cool and freezing levels below treeline.
Snowpack Summary
The ~40 cm of snow received last week has settled with little wind effect in most areas. Previous surfaces including sun crusts on solar aspects and wind slab below ridgelines and cross-loaded gulley features are buried and are hard to discern. The Feb10th drought layer is 50-100 cm deep and is the greatest concern.
Avalanche Summary
No new observations yesterday with observers in the Maligne and a helicopter flight in the Cavell Area. Several large avalanches were observed earlier this week. on the Feb 10th layer. These avalanches exhibited wide propagation primarily on big East facing alpine terrain.
Confidence
Intensity of incoming weather systems is uncertain
Problems
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.
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.