Avalanche Forecast

Archived

Mar 1st, 2024–Mar 2nd, 2024

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Good time to avoid all avalanche terrain and head to a local resort.

Give the new snow time to settle and bond.

A Special Public Avalanche Warning is in effect. Click the red SPAW link for details.

Confidence

High

Avalanche Summary

Observations were limited due to the weather but we were able to see one size 2.5 avalanche on a NE aspects on Little Tent Ridge that had a 200m wide propagation. The suspected failure plane is the Feb 3rd Crust. We suspect that a natural cycle is still ongoing.

A late day report also came in of a sz 3.5 skier remote from 75m away near Purple knob that ran full path taking out mature timber.

Snowpack Summary

55-85cm of recent snow is now overlying the Feb 3rd crust complex. Storm slabs and wind slabs can be expected in this new snow which will be easy to trigger with a skiers weight. A weak layer of facetted crystals also exists above and below this crust that has been producing moderate sheers. This new snow is beginning to overload this layer and cause a natural avalanche cycle. The November basal facets are alive and well and back on our radar as the February 2 rain crust is deteriorating and not locking in the weaknesses below as it once did. Skier weight has now been able to break through the Feb 2 rain crust in some places, which means that the basal facets can now be more easily affected.

This is a good time to avoid all avalanche terrain

Weather Summary

Light snow will continue overnight with accumulations of around 5cm snow. Winds are forecast to become more easterly overnight with peak speeds around 40km/hr. A grey-bird day is in store again with not much in the way of sun and temperatures around -15C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.