Avalanche Forecast

Archived

Feb 4th, 2024–Feb 5th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

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.

10-15cm of snow fell during this weather input. Once you get above 2000m the rain soaked snowpack turns more supportive and travel becomes much easier. A slight refresh to ski quality!

Confidence

Moderate

Avalanche Summary

Bad visibility on the drive today did not note any new avalanches. However a field trip in to the hero's knob drainage noted a wide spread avalanche cycle from the previous warm and wet weather to Size 2 on all aspects treeline and above.

Snowpack Summary

A field team went out in to the South part of the spray today where the weather stations say the most snow has fallen. We found about 8cm of new snow overlying the previous rain soaked surfaces which appears to be bonding well with the warmer temperatures. The slightly moist snow below is trying to dry out. This new snow is also sitting on a now breakable crust that isn't all that supportive until you get above 2000m. We did not get all the expected precip we were hoping for, but the ski quality has been slightly refreshed.

Weather Summary

Things are finally changing a bit. Weather stations are all saying about 10-15cm of snow in the last 36 hours. The temps remain warm about -5 and light winds. Monday will see a slight appearance from the sun mid day with day time highs around -6. Winds will continue to be light out of the SW.

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.

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.