Avalanche Forecast

Archived

Apr 12th, 2025–Apr 14th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Regions

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

Evaluate snow and terrain carefully to identify features of concern. Natural avalanches are unlikely yet human triggered avalanches remain possible. Monitor the overnight freeze and the afternoon warming patterns. The sun and warm air can rapidly increase avalanche triggering potential.

Confidence

High

Avalanche Summary

Friday's Icefield patrol did not note any new avalanches. Recently large cornice failures and small windslabs have been observed at alpine elevations. Earlier this week a size 3 deep persistent slab avalanche was observed in the alpine on a N-NW aspect.

Snowpack Summary

Strong winds last Wednesday with some new snow formed windslabs. The upper snowpack at treeline and below is a series of melt-freeze crusts and moist snow. The mid-pack and lower snowpack is dry, faceted and weak. The alpine and treeline snowpack on north aspects remains dry. Average treeline snow depth is around 100-150cm at the icefields area.

Weather Summary

Parker's ridge weather for Saturday night will be mainly clear, -11 °C, and light winds. Expect Sunday to bring sun, cloud, -5 °C, and light winds. Monday will bring flurries and -7 to 0 °C. Tuesday could have flurries and 6cm of snow.

Terrain and Travel Advice

Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.