Avalanche Forecast

Archived

Mar 25th, 2024–Mar 26th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Although conditions have improved, this is not the time to be skiing aggressive lines, as evidenced by the close call on Sunday (see Avalanche Summary). Multiple buried crusts and weak basal layers are still very much skier-triggerable.

Confidence

High

Avalanche Summary

No new avalanche observed or reported today.

One skier triggered avalanche size 3 occurred in Tent Bowl on Sunday. The avalanche was triggered after the fourth turn and the skier was carried down with it and buried up to their neck, but without any injuries. The avalanche depth varied from thin to thick with evidence of the March 20 interface, the February 2 crust, the basal facets and the ground. Some of the blocks were the size of a Ferrari. Please see the MIN report at https://avalanche.ca/map?panel=mountain-information-network-submissions%2F3a547b44-ea29-11ee-97c1-0a58a9feac02

Snowpack Summary

Surface crusts have formed on all terrain that is even slightly tipped towards the sun. On northerly aspects there is 20-30cm of recent storm snow. Winds have created some wind slabs in the alpine, including some reverse wind loading by northerly winds. All of this is overlying the March Temperature crust that is found on all aspects except high pure north alpine areas. So far, the bond with the new snow and the underlying crust is good. Deeper in the snowpack the February 3rd crust still exists but avalanche activity on this layer has decreased since the warm temps last week have settled out the snowpack. It is still worth digging and poking down to evaluate this layer.

When the sun comes out and the temperature rises, the avalanche hazard will increase.

Weather Summary

Tuesday will bring a mix of sun and cloud and very light flurries. Light/moderate NW winds will continue with daytime highs reaching -2C at treeline.

Be aware that when the sun does come out it packs a punch at this time of year and snow stability will quickly deteriorate on the solar aspects. Thin cloud can also lead to a "Greenhouse Effect" that can make the upper snowpack moist and unstable. Lots going on in Spring!

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Conditions may have improved, but be mindful that deep instabilities are still present.
Recent wind has varied in direction so watch for wind slabs on all aspects.
The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.

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.

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.