Avalanche Forecast

Archived

Mar 26th, 2023–Mar 27th, 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 unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

This is the time to stay disciplined and out of avalanche exposure. Choose low angle, and low consequence terrain.

Confidence

Moderate

Avalanche Summary

Several loose dry size 1-1.5 avalanches on all aspects occurred on Sunday in extreme unskiable terrain.

Several slab(30-40cm thick) avalanches size 1.5-2 occurred on Sunday on East to South aspects. This is likely on the March 12 facet/surface hoar/crust interface.

With more snow forecast, expect to see more avalanches of this nature.

Snowpack Summary

10-20cm of settled storm snow is on the ground with possibly another 15cm on Sunday night; it is likely to be dry on polar aspects and moist on solar aspects in the afternoon, and a crust in the morning. There has not been much wind with this storm but the storm snow is settling rapidly with the warm temperatures and solar radiation. We now have several buried crusts on solar aspects. Take the time to evaluate the bond between the new snow and crusts. A fracture line profile was recently done on a possible skier triggered sz 3 avalanche from a few days ago in the Murray Moraines drainage on a N aspect at 2200m. The failure layer was a layer of facets/depth hoar down 100cm. This layer was producing moderate sudden collapses. Also the propagation on this layer was over 200m. This layer has been noted in snow profiles throughout the region and rockies so be sure to dig down before committing to a feature. The slope that avalanched took out and buried numerous ski lines. Forecasters are still avoiding being on any steeper or large features due to high levels of uncertainty within the snowpack.

Weather Summary

Expect 5-15cm of snow Sunday night. Monday's temperature will be between -11c and -6c, along with light winds from the West.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Minimize exposure to sun-exposed slopes when the solar radiation is strong.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

Problems

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.

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.