Avalanche Forecast

Archived

Apr 17th, 2024–Apr 18th, 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.

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.

Recent new snow has given a nice reset to the region. Be aware of sluffing and newly formed wind slabs, especially at higher elevations.

Confidence

High

Avalanche Summary

Two naturally triggered loose dry avalanches up to size 2.0 were observed in extreme Alpine terrain on Wednesday.

Snowpack Summary

Recent storm snow totals are highly variable depending on drainage and elevation. On average 5cm of new snow fell overnight bringing recent storm snow totals to 30cm at Treeline. This fresh snow overlies a moist crust and is bonding well except at higher elevations. Wind slabs are evident at 2400m and above, and could be sensitive to human triggering. The deeper persistent weak layers are still a concern where the snowpack is thin or when the crusts break down with direct solar radiation and/or daytime heating.

Weather Summary

Thursday may start off at -18C!!!! Then it should be mainly sunny with cloudy periods in the afternoon. Temperatures will climb to -4C with light to moderate northerly winds.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Be cautious of sluffing.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
Recent wind has varied in direction so watch for wind slabs on all aspects.

Problems

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.