Avalanche Forecast

Archived

Nov 24th, 2020–Nov 25th, 2020

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Kananaskis.

Strong winds and increasing. Evidence of a fairly large avalanche in the past 48hr up to size 2.5 failing on the Nov.5 crust interface. The start zone were in steeper alpine features just below rock bands. Good skiing up high in sheltered areas.

Confidence

Moderate -

Weather Forecast

Steadily increasing winds through the day, eventually reaching up to 100km/h. There is a possibility of very light flurries later in the day. Most weather models are calling for 10cm of snow to fall on Wednesday.

Avalanche Summary

No new avalanches observed today. When skiing around we saw evidence of an older cycle up to size 2.5 running on the Nov. 5 crust layer. They looked to have stared from close to rock features that were loading the slope below.

Snowpack Summary

New layer found today down 40cm producing low end of moderate results on a surface hoar/new snow layer. Faceting above the Nov crust layer. The crust is buried 50 to 80cm deep and is producing moderate to hard compression test failures. In wind prone areas such as gullies and the lee side of ridges surface wind slabs 10 to 20cm thick have been observed. Cornices are much larger than normal for this time of year, failures have been observed in recent days. Overall the snowpack carries fairly well once above 2000m, but it is still relatively shallow with lots of slightly hidden hazards (rocks, stumps, etc.) lurking beneath.

Terrain and Travel

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Approach lee and cross-loaded slopes with caution.

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.