Avalanche Forecast

Issued: Dec 4th, 2018 4:23PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Wet.

Avalanche Canada cgarritty, Avalanche Canada

Reaching the alpine still involves rugged early season travel. With lots of sunshine in the forecast for Wednesday, you can expect increasingly active loose wet avalanche conditions if you make it there.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday night: Clear with cloudy periods. Light northeast winds.Wednesday: Sunny with some lower elevation cloud. Light northeast winds, reaching to moderate in the south of the region. Alpine high temperatures around -7.Thursday: Sunny with some lower elevation cloud. Light variable winds. Alpine high temperatures around -4, slightly cooler at lower elevations under a mild temperature inversion.Friday: Sunny with some lower elevation cloud. Light south or southwest winds. Alpine high temperatures around -3, slightly cooler at lower elevations under a mild temperature inversion.

Avalanche Summary

Two recent very large (size 3) avalanches were observed in the Joffre Lakes area on Saturday. These released from the high alpine northeast and northwest faces of Mt. Joffre and Mt. Matier, respectively. The evidence of the Mt. Matier slide features several 'step downs' as the slide progressively triggered deeper layers of the snowpack, all the way down to previous summer snow cover. Both slides likely released during last week's storm.Please submit any observations you have to the Mountain Information Network here.

Snowpack Summary

Increasing sunshine and warmth are expected to form a new sun crust on steeper sun exposed aspects over the coming days. Beneath this surface and on shaded aspects, the recent pattern of cold weather has been gradually transforming storm snow from last week into a layer of faceted (sugary) snow. This layer of faceting storm snow increases in depth from about 5-10 cm at 1600-2000 metres, where it sits above a rain crust, to around 20-30 cm in the alpine above 2000 metres, where the crust may not be present. Here, the storm snow is suspected to be bonding well to a settled mid snowpack.Above 2000m, alpine snowpack depths are approaching 175 cm, although recent reports suggest about half these depths around treeline in the south of the region. A crust/facet interface can be found near the ground in the alpine, but this may again be most prevalent in the north of the region. Although little is known about the reactivity of this layer, recent observations in the north of the region show that it was reactive during last week's storm. It is thought that there is insufficient snow for avalanches below 1500 m.

Problems

Loose Wet

An icon showing Loose Wet
Strong sunshine is likely to destabillize surface snow and promote loose wet avalanche activity on sun-exposed slopes on Wednesday. Loose wet slides may occur naturally or with a human trigger.
Be aware of low angle December sun targeting its radiation on steeper slopes.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: South East, South, South West, West.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 1.5

Valid until: Dec 5th, 2018 2:00PM