Avalanche Forecast

Archived

Dec 16th, 2025–Dec 17th, 2025

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 possible, human triggered probable.

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.

The avalanche cycle has passed its peak; however the danger remains elevated for the rest of the week as more snow falls. Cooling temps have stabilized the snowpack below treeline, but overhead hazard remains a concern, and treeline and alpine areas remain reactive to human triggering. Better conditions ahead with the next snow.

Confidence

Avalanche Summary

We continue to be in the midst of a widespread avalanche cycle, although on Tuesday, the avalanche activity slowed down due to cooling. However, over the past few days there have been many large natural and explosive-triggered avalanches all over the place, some running down as wet debris in the runout zones. Natural avalanches up to size 3.5 have been reported. We expect avalanche activity to continue as the next wave of snow arrives overnight Tuesday.

Snowpack Summary

With the continued storms over the past week, there is now a 50-100 cm slab overlying the Nov 22 facet layer. This layer has been producing large avalanches, however, Tuesday's cooling temperatures took the avalanche cycle off its peak as we cooled 7 degrees in 12-hours. Low elevations have stabilized as they got soaked and then cooled, but treeline and above remain dry snow and reactive avalanche conditions.

Treeline snowpack depths range from 60-140 cm.

Weather Summary

The parade of storms continues.

Strong NW flow continues with another system crossing the area Tuesday night and Wednesday. We expect another 20 cm by Wednesday and another 10 on Thursday, accompanied by strong winds and freezing levels dropping over the next few days.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Continue to make conservative terrain choices while the storm snow settles and stabilizes.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.