Avalanche Forecast

Archived

Apr 9th, 2025–Apr 10th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Below Threshold.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Regions

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

Sunny and warm for Thursday, which will produce a daily melt-freeze cycle. Avalanche danger ratings reflect the highest danger for the day. The snowpack in Banff, Yoho and Kootenay remains weak, despite the onset of spring, and we remain suspicious of all steep alpine terrain on shaded aspects where no crusts exist.

Confidence

Moderate

Avalanche Summary

The local ski areas continue to mitigate size 1 windslabs and small cornice buildup in leeward, alpine areas and on Tuesday, HWY 93 road patrol, one size 2 recent cornice failure on Crowfoot mountain, scrubbing to the ground in extreme terrain.

Snowpack Summary

Surface crusts are found in most locations except north-facing alpine zones. The integrity of the snowpack is based mostly upon the strength of the surface crust when it refreezes overnight (or doesn't). In areas with no surface crust, concern remains due to the weak basal facets, which have plagued the mid and base of the snowpack all winter. This makes most steep, alpine terrain in the shallow snowpack areas of BYK suspect, and we have low confidence in this snowpack.

Weather Summary

Wednesday evening looks clear, giving a good possibility of a freeze for Thursday morning.

Thursday and Friday look like sunny days, with valley bottom highs of +10 and freezing levels reaching 2500 m on Thursday. Slow cooling will follow into the weekend, with classic spring weather - mostly clear but some rain and snow flurries but no significant accumulation (~5 cm).

Terrain and Travel Advice

Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.
Start your day early and be out of avalanche terrain during the heat of the day.

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.