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Avalanche Forecast

Archived

Mar 12th, 2024–Mar 13th, 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, Ghost.

The snowpack is very tricky right now and sensitive to triggering. Careful route selection and intimate understanding of the snowpack is essential for safe travel.

Confidence

High

Avalanche Summary

No new avalanches have been reported today. However this last Sunday, three skier triggered avalanches occurred, one of which there was a fatality. Check the Min reports for further details.

Snowpack Summary

5-20cm of recent snow overlies previous wind slabs and sun crust on solar aspects. Expect moist snow on solar aspects if the sun comes out. The winds on Tuesday were moving snow along ridges, so expect a new generation of wind slabs on lee features.

The snowpack is quite complex as all of the following layers are possible to trigger avalanches:

  1. Buried sun crusts on solar aspects down 20cm will provide a good sliding layer for the new snow to slide if the sun comes out. Be aware of what is above you.

  2. This last weekends wind slabs are now buried up to 20cm and have possibly been one of the triggers to wake up deeper layers in the snowpack.

  3. The February 2 crust is down approximately 70-100cm and has started to facet out around itself, providing a good sliding layer. This layer was the trigger for most of the avalanches on Sunday.

  4. The basal facets found near the bottom of the snowpack have been triggered by failures of the above layers.

Careful route selection is key as well as taking a closer look at the snowpack to understand where all the weaknesses lie.

GHOST FORECAST AREA

The Ghost area has more snow than usual. With this warming trend, pay close attention of what is above you. Wet loose avalanches are possible in this forecast region so ice climbers should choose routes appropriately.

Weather Summary

Wednesday will be a mix of cloud, flurries(maybe 5cm) and a bit of sun in the afternoon. Temperatures in the alpine are expected to climb to a balmy -2c. For Wednesday only, the winds will be from the North at 30km/hr.

The weekend is looking rather warm and avalanche conditions will likely increase.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Remote triggering is a concern, watch out for adjacent and overhead slopes.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.