Avalanche Forecast

Archived

Apr 13th, 2023–Apr 14th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely.

Regions

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

A skier triggered avalanche occurred on the approach to the north glacier on Mt. Athabasca today, along with a number of natural avalanches to size 3 in the area. The deep persistent weak layer is most likely to be triggered in thin-to-thick snowpack transition zones.

The Icefields Parkway will be closed at 12:00 pm on Friday, April 14, 2023 from Parker Ridge to the Big Bend parking lot. The Icefields Parkway is expected to open at 3:00 pm Friday, April 14, 2023.

Confidence

Moderate

Avalanche Summary

A size 2 skier remote or accidental triggered avalanche was observed on the regular approach to the north glacier on Mt. Athabasca. Several other large avalanches from the last couple of days were also observed. These avalanches are mostly occurring on east and west aspects at tree line and above. The are either running on a mid-pack persistent weak layer or stepping down to the deep persistent layer.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Up to 20cm of snow sits on multiple crusts up to 2400m. Snow pit tests are showing results in the weak facet crystals below these crusts on south aspects. Above 2400m the surface snow is dry. The Snowpack below 1800m is in a daily melt-freeze cycle. The mid pack above this elevation consists of multiple layers of sun crusts or facets. Depth hoar and basal facets make up the base of the snowpack.

Weather Summary

Friday

A mix of sun and cloud.

Precipitation: Nil.

Alpine temperature: High -5 °C.

Ridge wind southwest: 10-25 km/h.

Freezing level: 1700 metres.

Saturday

Mainly cloudy with isolated flurries.

Precipitation: Trace.

Alpine temperature: Low -8 °C, High -4 °C.

Ridge wind southwest: 15 km/h gusting to 40 km/h.

Freezing level: 1800 metres.

Terrain and Travel Advice

Minimize exposure to sun-exposed slopes when the solar radiation is strong.
Remember that the snowpack will be significantly different at higher elevations than lower down.

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.