Avalanche Forecast

Archived

Apr 17th, 2025–Apr 20th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

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

Forecasters are still finding good skiing on sheltered northerly aspects. Start your trip early and plan to be back at the trailhead before the daytime heating and/or solar radiation effects the snowpack. Check out Avalanche Canada's blog on Spring Conditions for some good tips.

Confidence

High

Avalanche Summary

One recent sz 2.5 in the Miners Gully. Likely cornice triggered.

Snowpack Summary

Wind slabs are evident in the alpine on all aspects. While these slabs are not deep, they could be sensitive to triggering where the underlying surface is a smooth crust. Otherwise, expect a melt-freeze surface layer (or near surface) on all solar aspects as well as all aspects at lower elevations. Higher elevation northerly aspects still hold dry snow. Cornices are starting to sag in the mid-April heat, and some recent collapses have been observed.

Timing is everything. As surface crusts break down during the day the stability will begin to decrease. Start early and finish early.

Weather Summary

Friday looks to be mainly clear with a daytime high of -3C and freezing levels around 2300m. No new snow is foreast and winds are expected to be light out of the NW.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Even brief periods of direct sun could produce natural avalanches.
Avoid shallow snowpack areas, rocky outcrops, and steep terrain where triggering is most likely.
Wind slabs are isolated, but may remain reactive.
Be careful with wind-loaded pockets, especially near ridge crests and rollovers.
Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.

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 Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.