Avalanche Forecast

Archived

Apr 2nd, 2024–Apr 3rd, 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.

There is uncertainty around how much precipitation will come in late Tues night.

The more new snow we receive, the more the hazard will increase.

Confidence

Moderate

Avalanche Summary

Sunshine reported a cornice failure today on an NW aspect size 2 as well as some wet loose size 1. No other avalanches were reported.

A size 2 slab was remotely triggered from 50m on April 1st in the Purple Bowl at Lake Louise. The slab was reported to be 60cm deep and 75m wide. This would be a northwest aspect at around 2500m and would be the skier's right of a similar event triggered on the February 3rd layer just over a week ago.

Snowpack Summary

Up to 20cm of storm snow is forecasted Tues night, this will overlie a variety of crusts up to ~2800m on solar aspects, and up to ~2300m on northerly aspects. In the high alpine, this will overlie settled and wind-affected snow

Our main concern for persistent layers is shallow snowpack areas on northerly alpine aspects where no crusts are found in the upper snowpack and the midpack is thinner/weaker. Triggering the Feb 3 facet/crust layer and basal depth hoar remains possible

Weather Summary

Tues night: Strong winds from the West, followed by precipitation up to 20cm. Temperatures will begin to fall.

Wednesday: Cloudy with sunny periods. Continued cooling, light ridge wind gusting up to 45km/h. Freezing level 1800m. Precip nil.

Thursday: Cloudy with sunny periods. High -5°C. Freezing level valley bottom.

Click here for more weather info.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Loose avalanches may start small but they can grow and push you into dangerous terrain.
Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.

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.

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.

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.