Avalanche Forecast

Archived

Mar 14th, 2023–Mar 15th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

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 night surprised us with a welcomed 20cm. It came in as rain first and then transitioned to snow at lower elevations. Ski quality should improve with this.

Confidence

Moderate

Avalanche Summary

Several windslabs in the bow valley corridor this morning, including miners gully, the shelf on ships prow and the bowl on Stewart Charles. None of which stepped down on the weak basal snowpack. Otherwise not much noted on a road patrol on the spray this morning.

Snowpack Summary

An additional 20 cm of snow overnight brings our total from this storm to 25cm. This now buries sun crusts on solar aspects (S-W) and facets and wind scoured surfaces elsewhere. Generally a weak snowpack. Natural avalanches are possible and the consequences would be significant because any trigger would likely make the entire snowpack slide.

Weather Summary

Wednesday will see a mix of sun and cloud with a few flurries here and there. Winds will be out of the NW and Moderate in strength.

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.