Avalanche Forecast

Archived

Mar 20th, 2025–Mar 23rd, 2025

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 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.

Regions

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

Stick to low angle well supported terrain and limit your exposure to overhead features. If the sun comes out, watch for stability to deteriorate on solar aspects throughout the day.

Confidence

High

Avalanche Summary

Continued sporadic natural avalanche activty up to sz 2 from mainly N and E aspects at treeline and above. Treat any avalanche terrain that has not slid as suspect.

Snowpack Summary

Fresh wind slabs in the alpine were building on Thursday 10cm to 30cm deep. The top half of the snowpack is a 40-80cm dense slab that sits on top of 40-80cm of depth hoar and facets. This interface between the two is the January 30th interface and has produced repeatable sudden collapse test results. This layer has been failing on most of the recent avalanches. Unfortunately we will be in this pattern for the foreseeable future. Many recent avalanches have also stepped down to the basal facets and involved the entire snowpack. Repeated settlements are still being encountered by forecasters as they travel.

Weather Summary

A mix of sun and cloud with 5-8cm of convective snow over the next 24hrs with strong westerly winds. Temperatures will be up -5C during the heat of the day. If the sun comes out watch for stability to rapidly decrease on solar aspects.

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.
Keep in mind that human triggering may persist as natural avalanches taper off.

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.