Avalanche Forecast

Archived

Apr 10th, 2025–Apr 11th, 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 unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

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

The winds have increased and we are expecting new snow. Watch for fresh wind slabs potentially down into tree line.

Confidence

Moderate

Avalanche Summary

Small windslab avalanches and large natural cornice avalanches have been observed in Jasper or just to the south of Jasper over the last couple of days.

Snowpack Summary

New windslabs are forming from strong south winds and new snow. 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

Friday

Cloudy with sunny periods and isolated flurries.

Precipitation: Trace.

Alpine temperature: High -5 °C.

Ridge wind southwest: 20 km/h gusting to 70 km/h.

Freezing level: 1700 metres.

Saturday

Flurries.

Accumulation: 6 cm.

Alpine temperature: Low -9 °C, High -6 °C.

Ridge wind west: 15-35 km/h.

Freezing level at valley bottom.

Terrain and Travel Advice

Make conservative terrain choices and avoid overhead hazard.
Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.