Avalanche Forecast

Archived

Mar 12th, 2023–Mar 13th, 2023

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

Monday is expected to be stormy and snowy. Give all avalanche terrain a miss until the storm passes and the very fragile snowpack has time to adjust to the new load.

Confidence

Moderate

Avalanche Summary

No new avalanches reported or observed today.

Snowpack Summary

Sun crusts continue to form on steep solar aspects. Generally a weak snowpack. The surface wind slab at tree line and above is slowly gaining strength but is still producing planar results down 20cm from the surface. Natural avalanches are possible and the consequences would be significant because any trigger would likely make the entire snowpack slide.

Weather Summary

A storm arrives. Forecast models are calling for anywhere between 15-25cm starting tonight and throughout Monday. The storm will come in warm with day time highs of -4. The winds will be howling out of the SW to 60km/h. Freezing levels around 2000m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

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.

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.