Avalanche Forecast

Archived

Feb 5th, 2024–Feb 6th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

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

15-20cm of storm snow has refreshed the skiing. You very much feel the rain/temp crust below but is fully supportive to skier traffic. Enjoy the reasonable skiing while its here!

Confidence

Moderate

Avalanche Summary

Good visibility on the spray noted some loose dry snow moving in the steepest alpine headwall features. Otherwise no new slab activity was observed.

Snowpack Summary

A field team went to Burstall pass today. Top elevation was 2400m and the rain/temp crust still exists and is fully supportive to skier traffic. There is about 10-20 cm on the crust and seems to be bonding well. Below this is the arctic facets, these are currently showing rounding behaviour and are bonding well. Facets and depth hoar still make up the remaining snowpack. Tests today showed no notable results in treeline features.

Weather Summary

Tuesday will bring sunny periods and isolated flurries.

High of -6 and 25km winds out of the SW

Freezing levels to hover around 1800m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Wind slabs may be poorly bonded to the underlying crust.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

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.