Avalanche Forecast

Archived

Dec 13th, 2025–Dec 14th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

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

The avalanche hazard will remain elevated as warming temperatures, strong to extreme winds, and more snow arrives on Sunday.

Mt. Simpson will be closed all day on Sunday, December 14, as avalanche control operations will be underway. Go to: https://www.pc.gc.ca for more details

Confidence

Moderate

Avalanche Summary

Avalanche control at local ski hills on Saturday produced widespread results up to size 3. These slides failed on a combination of wind and persistent slabs. In addition to widespread explosive-triggered avalanches, ski patrol reported a size 3 vehicle remote avalanche triggered by helicopter rotor wash. The natural avalanche cycle is still active; our field team observed a size 2.5 natural that released on the persistent problem.

Snowpack Summary

30-60cm of storm snow fell last week, accompanied by strong SW winds. Fresh wind slabs are prevalent in the alpine and into treeline up to 60cm deep. 60-80cm of snow sits over a mid-November interface of facets that are particularly touchy when they are associated with a sun or temperature crust that exists in some places well into the alpine. Further down, the November 13 rain crust extends to 2100-2300m.

Weather Summary

Southwest flow brings precipitation starting Sunday and continuing into early next week. Lower elevations will see rain/snow mix. Upper elevations are forecast for 20–50 cm of snow. Unseasonably warm temperatures keep the freezing level near 2000m Sunday and Monday. This pulse will be accompanied by strong to extreme southwest winds.

For more info, click here for Environment Canada tables.

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.

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.

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.