Avalanche Forecast

Archived

Feb 3rd, 2024–Feb 4th, 2024

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.

Up to 10cm of fresh snow with another 10cm on the way with moderate winds. Hazard levels will depend significantly on how well the new snow bonds with the underlying crusts. Take extra time to evaluate this bond as you travel through different elevation bands and on various aspects. Choose conservative terrain for the next few days.

Confidence

Low

Avalanche Summary

No new avalanche were observed, but weather conditions made for limited observations.

Snowpack Summary

A big change is occurring. Up to 10cm of warm, moist snow has fallen at Treeline through the day on Saturday. This snowfall started off very warm, so hopefully it will stick to the recently formed raincrust underneath. However, with the deep penetration of the previous rainfall and warm temps, buried layers of moist snow will persist for some time. Travel may be difficult until the temperatures cool down and freeze the rain saturated layers. Another 10cm of slightly cooler snow is possible in the next 24 hours, with moderate NE winds. This will likely lead to fresh wind slab development on NW, W and SW slopes, especially at higher elevations. In alpine areas, this incoming snow may not bond well to the previous surfaces, but at lower elevations it likely will. Backcountry users should be very curious over the next few days, dig frequently, and carefully evaluate the effects of this big weather change at various elevations and on various aspects.

Weather Summary

It finally snowed again! Up to 10cm at Treeline fell through the day on Saturday, with the Snowfall Warning continuing into Sunday. An additional 10cm is possible. Initially the winds will be moderate from the NE, and then it sill switch to light SW late Sunday afternoon. Temperatures should range from -12 to -9C. The snowfall should end around midnight Sunday, with mainly cloudy conditions by Monday morning.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Wind slabs may be poorly bonded to the underlying crust.
Wind slabs are most reactive during their formation.
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.
Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.

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.