Avalanche Forecast

Issued: Dec 15th, 2018 4:45PM

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

Avalanche Canada kdevine, Avalanche Canada

A Special Public Avalanche Warning (SPAW) is in effect for this region. Natural avalanche activity has decreased to some degree, but THE POTENTIAL FOR HUMAN TRIGGERED AVALANCHES REMAINS LIKELY.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

SATURDAY NIGHT - Mainly cloudy with isolated flurries / south winds, 20-40 km/h / alpine low temperature near -9SUNDAY - Mainly cloudy with flurries, 5 cm / south winds, 30-40 km/h / freezing level 1500 m / alpine high temperature near -2MONDAY - Flurries, 10-15 cm / south to southwest winds, 25-60 km/h / freezing level 1500 m / alpine high temperature near -3, low temperature near -6TUESDAY - Snow, 10-20 cm / south to southwest winds, 25-45 km/h, gusting to 60 km/h / freezing level 1400 m / alpine high temperature near -4, low temperature near -6

Avalanche Summary

Avalanche activity continues in the North Columbia region with explosives triggered avalanches to size 3.5, as well as natural and human triggered avalanches to size 2 being reported on Saturday.Natural and explosives triggered avalanches up to size 3, and human triggered avalanches to size 2.5 were reported in the region on Friday. Several of these avalanches were triggered from a distance (remote triggered). On Friday, a size 3-4 natural avalanche was reported to have run full path, burying a road under several metres of debris on the west side of Kinbasket Lake. This avalanche occurred in the northern reaches of the North Columbia region, close to the boundary of the Cariboo region. These full path avalanches can catch people by surprise, especially when there is very little snow in the valley bottoms. A report of this avalanche can be found on the Mountain Information Network here

Snowpack Summary

60-90 cm of recent storm snow sits on a weak layer of facets (sugary snow), surface hoar (feathery crystals), and a sun crust (on south facing slopes). Strong winds have promoted widespread slab formation.A weak layer from mid November is now buried up to 150 cm and consists of surface hoar and a sun crust. The potential may exist for smaller avalanches to step down and trigger this deeper layer, resulting in large avalanches. The most likely place for this layer to be a problem is on steep, south facing slopes at treeline where the surface hoar sits on the sun crust.At the base of the snowpack is a crust that formed in late October. Concern for this layer is dwindling but it may still be worth considering in places such as steep, rocky, alpine terrain, especially where the snowpack is shallow. It would likely take a large trigger such as a cornice fall to produce an avalanche on this layer.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Up to 90 cm of new snow sits on a weak layer of facets (sugary snow) surface hoar (feathery crystals) and sun crust (on south facing slopes). Wind loaded pockets could have 200+ cm of snow over this layer.
Avalanches on this layer may step down to deeper layers resulting in very large avalanches.Remote triggering is a concern, watch out for adjacent slopes.Use conservative route selection, choose low angle and supported terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 16th, 2018 2:00PM