Avalanche Forecast

Archived

Nov 12th, 2023–Nov 13th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

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

A fatal avalanche incident occurred Saturday involving ice climbers in the Ranger Creek area. Lee and cross-loaded features in the Alpine should be avoided.

Confidence

Low

Avalanche Summary

Numerous wind slabs and loose dry avalanches occurred Saturday up to size 2.0. Many slopes avalanched, then quickly reloaded and slid again. While natural activity tapered on Sunday, avalanche control in an alpine basin with N and E aspects produced numerous size 2.0 avalanches.

A fatal avalanche occurred on Saturday involving ice climbers on the Spray Road. A size 2.0 naturally trigged slab avalanche failed in alpine terrain, ran over a cliff and caught two people in a terrain trap. Unfortunately one person did not survive. Avoid exposure to avalanche terrain as another rapid loading event is possible Monday afternoon.

Snowpack Summary

We now have a persistent weak layer (Nov 10) that is down about 20-40cm in the alpine, 10cm at treeline. Very little is known about this Nov 10th temperature crust, but it appears to be spotty aspect wise, very reactive(slippery) and estimated to be up to 2400m. Wind slabs built very quickly Saturday with lots of visible wind transport. Overall snowpack depth and character is largely unknown as it is early season. From what we have seen and heard total snow depth varies from 10-60cm. Coverage is very inconsistent with LOTS of hidden hazards.

Weather Summary

Monday will be a mix of sun and cloud with a storm rolling through in the afternoon. Strong to extreme winds are expected midday, followed by about 5cm of snow. Temperatures should be near -1C as a high.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Avoid lee and cross-loaded terrain.
Be carefull with sluffing in steep terrain, especially above cliffs and terrain traps.
Avoid terrain traps where the consequence of any avalanche could be serious.

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.

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.