Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Dec 26th, 2022–Dec 28th, 2022

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 unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

Banff Yoho Kootenay, Little Yoho, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N, Field.

Avalanche control is planned for Mt Bourgeau and Eagle Mountain on the Sunshine Village Access road on Wednesday December 28th. No access to these areas on Dec. 28th. Click here for a description of the area, and maps.

Confidence

Moderate

Avalanche Summary

The snow safety team at the Lake Louise Ski Resort triggered several size 2 avalanches today in steep alpine terrain. These were 25-60 cm deep windslabs and were triggered by a mixture of ski cuts, skiier remotes and explosives. At least one occurred on a reloaded bed surface. At treeline, things were cracking and whumphing but the slabs being triggered were much smaller and softer.

Snowpack Summary

Strong westerly winds that occurred over the weekend have blown 20-30 cm of recent snow into widespread windslabs in the alpine and some treeline areas. These slabs sit atop a weak layer of facets and surface hoar (Dec. 17th interface) and have been producing skiier triggered avalanches to size 2. Below this, the snowpack is generally facetted with the largest facets and depth hoar near the bottom.

Snowpack depths at treeline range from 80-140 cm throughout the region. Snow profile at Pulpit from Tuesday here.

Weather Summary

A final low pressure system and associated cold front is moving through on Wednesday before drier and colder conditions arrive.

Wednesday: Temperatures at treeline -3 to -5. Alpine winds light to moderate from the SW and 2-5cm snow.

Thursday: Temperatures at treeline ~ -7 and cooling to -10 by end of day. Alpine winds light to moderate from the SW. 1-2 cm in the AM and clearing in the afternoon

Friday: Temperatures at treeline -5 to -10. Alpine winds light to moderate from the SW. Trace of new snow.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Uncertainty is best managed through conservative terrain choices at this time.

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.

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.

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.