Avalanche Forecast

Archived

Apr 27th, 2025–Apr 28th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

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

The deep persistent problem is still a problem. Watch for isolated wind slabs in the high alpine and thin to thick snowpack areas where triggering the deep persistent slab is more likely.

Start and end your day early to beat the daytime warming!

Confidence

Moderate

Avalanche Summary

Three size 2 deep persistent slab avalanches were observed on Saturday (26th) along the Icefields Parkway, along with numerous wet loose avalanches up to size 2. Northerly aspects in the alpine were also beginning to produce wet loose avalanches up to size 1 on steep terrain features.

Snowpack Summary

In sheltered northerly slopes above 2600m, anywhere from 5-20 cm of soft snow exists. Isolated wind slabs exist on wind exposed lee slopes in the alpine. The upper snowpack at treeline and below is a series of crusts. In the alpine, the lower snowpack is dry, faceted, and weak. High north aspects offer the best spring riding conditions, though the snowpack remains susceptible to triggering deeper, unstable layers.

Weather Summary

Freezing level will drop to valley bottom on Sunday evening. Monday will see a mix of sun and cloud, winds gusting to 40km/h and with an alpine high of 0 °C. Freezing levels will reach 2200m. Tuesday will bring similar conditions but with a little more sunshine.

Terrain and Travel Advice

Back off slopes as the surface becomes moist or wet with rising temperatures.
Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

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.