Avalanche Forecast

Archived

Apr 17th, 2025–Apr 18th, 2025

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

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.

Start and end your day early. Friday will get very warm in the afternoon and evening, which will increase the avalanche hazard.

The deep persistent layers are still in the snowpack. Be careful on high north aspects where there are no crusts above these layers.

Confidence

Moderate

Avalanche Summary

Recently large cornice failures and small wind slabs have been observed at alpine elevations.

On Sunday a size 3.5 deep persistent avalanche was observed on the subpeak to the east of Mt. Saskatchewan.

Snowpack Summary

5-20 cm of recent new snow exists in sheltered areas. Wind slabs exist on all aspects in the alpine due to recent variable wind loading. The upper snowpack at tree line & below is a series of melt-freeze crusts and moist snow. The mid-pack and lower snowpack is dry, faceted and weak. High north aspects do not have any of crusts in the upper snowpack which may make it easier to trigger the deep persistent layer.

Weather Summary

Thursday Night

Clear with cloudy periods.

Precipitation: Nil.

Alpine temperature: Low -3 °C.

Ridge wind light to 25 km/h.

Freezing level at valley bottom.

Friday

A mix of sun and cloud with isolated flurries.

Precipitation: Trace.

Alpine temperature: High +2 °C.

+14 in Jasper townsite

Ridge wind west: 15 km/h.

Freezing level: 2500 metres.

Saturday

Mainly cloudy with scattered flurries.

Accumulation: 4 cm.

Alpine temperature: Low -4 °C, High 0 °C.

Ridge wind west: 15-30 km/h.

Freezing level: 2200 metres.

Terrain and Travel Advice

Pay attention to cornices and give them a wide berth when traveling on or below ridges.
A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.

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.

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.

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.