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 10th, 2024–Dec 11th, 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 unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

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

NW winds have gotten to much of the higher terrain, but soft snow still exists in sheltered areas. Be cautious if entering wind effected terrain and give the deep persistent problem some respect as we are still seeing triggering with light loads.

Confidence

Moderate

Avalanche Summary

A team in the Little Yoho area today saw little evidence of new avalanche activity on Tuesday

However, local ski hills were reporting continued natural and explosive triggered windslabs and deep persistent slabs

Notables included several slides to ground in the Lipalian area in the LL backcountry and a size 2 and 2.5 in NW and SE aspect alpine in the Delirium Dive area of the Sunshine backcountry. These failed on the basal facets with relatively small loads (2kg explosives)

Snowpack Summary

20-40 cm of recent snow has been blown by S/SW winds into windslabs in exposed alpine and treeline locations. In sheltered areas, non-wind effected snow sits on a layer of facets, suncrust and isolated surface hoar that was buried on Dec. 7th. Below this is a weak and facetted, early season midpack with two crust/facet layers near the bottom of the snowpack (Nov. 9th and Oct. 20th interfaces). Total snowpack depths at treeline are 60-100 cm.

Weather Summary

A ridge of high pressure sits over the area bringing cooler air and stable weather for a few days. Skies should be mostly clear with few clouds, moderate NW winds and high temperatures of ~ -5 to -10. We might see some light precip Wednesday overnight but nothing significant until the weekend.

Terrain and Travel Advice

  • Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
  • 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.

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.