Avalanche Forecast

Archived

Apr 29th, 2024–Apr 30th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

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

There's a lot of uncertainty with snowfall amounts and timing but most forecasts agree that the next couple days will be fairly stormy with elevated northerly winds.

Expect avalanche activity in steep alpine terrain.

Confidence

Moderate

Avalanche Summary

A few small loose dry avalanches were observed in steep alpine terrain on a flight in the Banff area on Monday.

A size 1 windslab was triggered by a ski cut by Sunshine Village snow safety in a steep alpine feature.

Snowpack Summary

20-30 cm of storm snow remains dry on sheltered N slopes above ~2400 m and is moist or refrozen on all other aspects. This new snow sits over crusts on all aspects except high N slopes where it overlies dry snow.

The mid-pack Feb 3 persistent layer (crust/facet layer) and basal depth hoar remain the most prominent features in the snowpack but have been dormant since the last temperature spike. These layers are a greater concern in thin snowpack areas on north slopes above 2300m.

Weather Summary

Unstable weather with lots of convective activity over the next few days means that snowfall amounts will be highly variable and difficult to predict.

Generally, we can expect cool conditions with freezing levels staying below 2000m.

Tues: 5-10cm with some models showing up to 30cm. Moderate NW winds.

Wed: 5-10cm. Strong N winds

Thurs: Clearing trend, winds NE easing to light

For more detailed weather click here.

Terrain and Travel Advice

Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

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.