Avalanche Forecast

Archived

Mar 23rd, 2025–Mar 24th, 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 and human triggered avalanches likely.

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 possible, human triggered probable.

Regions

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

Natural avalanche activity is still being observed and human triggering of avalanches remains likely. It also looks like the avalanche hazard may increase again on Tuesday with precipitation, wind, and rising temperatures in the forecast. It won't take much to overload our fragile snow pack.

Confidence

Moderate

Avalanche Summary

A field team observed 3 new size 2 natural avalanches in the icefields area on Saturday. They appeared to be a mix of the wind slab, persistent slab, and deep persistent slab problems, which occurred in steep rocky terrain in the alpine and at tree line.

They also noted very large whoomphs while traveling on skis, indicating the snowpack is still primed for triggering large avalanches.

Snowpack Summary

Wind slabs exist in lee features throughout tree line and alpine areas. The 70-90 cm from earlier in March has settled into a supportive slab. Below this, the snowpack is complicated and reactive, having multiple crusts and facet layers including the deep persistent basal layer.

Weather Summary

Monday

A mix of sun and cloud with isolated flurries.

Alpine temperature: High -4 °C.

Ridge wind west: 20 km/h gusting to 55 km/h.

Tuesday

Flurries.

Accumulation: 11 cm.

Alpine temperature: Low -6 °C, High 0 °C.

Ridge wind southwest: 15 km/h gusting to 45 km/h.

Wednesday

Mainly cloudy with isolated flurries.

Alpine temperature: Low -1 °C, High 0 °C.

Ridge wind south: 10-30 km/h.

Terrain and Travel Advice

Make conservative terrain choices and avoid overhead hazard.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.

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.

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.