Avalanche Forecast

Issued: Feb 2nd, 2019 4:37PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Persistent Slabs.

Avalanche Canada kdevine, Avalanche Canada

Natural avalanche activity has tapered off to some degree, but human triggered avalanches remain likely. Conservative terrain selection is recommended.

Summary

Confidence

Moderate -

Weather Forecast

SATURDAY NIGHT - Mainly cloudy with isolated flurries / southwest switching to northeast winds, 10-20 km/h / alpine low temperature near -15SUNDAY - Mainly cloudy with isolated flurries, 5 cm / northeast winds 10-15 km/h / alpine high temperature near -20MONDAY - A mix of sun and cloud / northeast winds 10-15 km/h / alpine high temperature near -17TUESDAY - Mainly sunny / northeast winds, 10-15 km/h / alpine high temperature near -13

Avalanche Summary

Avalanche activity continued on Saturday. Natural avalanches to size 3, explosives triggered avalanches to size 2.5, and human triggered avalanches to size 2 were reported. Several of the human triggered avalanches were triggered remotely and they failed on the mid January persistent weak layer.A widespread natural avalanche cycle to size 3.5, and explosives triggered avalanches to size 3.5 were reported on Friday, as were numerous human triggered avalanches to size 2. Many of these were remote triggered (triggered from a distance). Some of these avalanches failed within the new storm snow, but many of them reportedly failed on a persistent weak layer that was buried in mid January.Human triggered avalanches failing on the mid January persistent weak layer have been reported almost daily for the past two weeks in the North Columbia region.On Tuesday, in the neighboring Glacier National Park region, a human triggered size 3 avalanche occurred on a steep southeast facing slope in the alpine. There is a detailed report on the Mountain Information Network here

Snowpack Summary

The North Columbia region wins the storm with 30-90 cm of snow since Thursday. Average total amounts since Thursday are in the 50-70 cm range. This new snow sits on surface hoar (feathery crystals), facets (sugary snow), wind slabs and a crust on sun-exposed slopes.A persistent weak layer that was buried in mid January is now buried 50-100 cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer has been most reactive at treeline and below, and was very reactive during the height of the recent storm. It is uncertain how reactive this layer will be with temperatures dropping, but it may still be reactive to human triggers.

Problems

Storm Slabs

An icon showing Storm Slabs
30-90 cm of new snow has fallen in the region since Thursday. The new snow will likely need some more time to bond to the underlying snow.
If triggered, storm slabs may step down to deeper layers and result in even larger avalanches.Avoid steep, unsupported slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs
50-100 cm of snow is now sitting on a persistent weak layer of surface hoar and crust. The North Columbia region has been the "hot spot" of activity on this layer, with more reactivity reported here than in neighboring regions.
Any steep opening in the trees should be treated as suspect right now.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Feb 3rd, 2019 2:00PM