Avalanche Forecast

Issued: Feb 10th, 2013 10:07AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Synopsis: A series of frontal systems are expected to bring generally light precipitation to the region through the forecast period.Monday: Flurries. Freezing level around 900m. NW winds gusting to 40 km/h at ridgetop.Tuesday: Around 5cm new snow. Freezing level around 1200m in the afternoon. Westerly winds gusting to 60 km/h at ridgetop.Wednesday: Flurries or light snow in the morning, mostly dry in the afternoon. Freezing level around 600m. Light NW winds.

Avalanche Summary

Cornice releases in the alpine and a glide crack release at low elevation (all size 2) were reported in response to warm temperatures. Loose wet avalanches were also reported on steep solar aspects.

Snowpack Summary

Around 30-40cm new snow fell on average during recent storms, which ended on Friday. The Coquihalla area received a little more (up to 65 cm). Consistent southwesterly winds during the storm period redistributed the new snow into wind slabs and grew cornices on lee terrain features in the alpine and at treeline. The recently buried surfaces (Feb 3rd interface) are old wind slabs (behind ridges, ribs and on lee slopes) and sun crusts (on south and west facing slopes). In isolated locations, this interface comprises small surface hoar crystals. Down a further 20-50 cm sits a persistent interface comprising of crusts, facets and surface hoar crystals. This layer is now mostly unreactive, with only oneĀ  size 2 avalanche reported (on Feb 6th) since the end of January. If it were to be triggered again, the most likely spot would be a steep convex roll on a sheltered north aspect slope around treeline. A recent Rutchblock test gave a score of 6 with a partial block release in the Duffey Lake area. The mid and lower snowpack pack layers are generally well settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Isolated pockets of wind slab remain behind ridges and ribs in exposed areas. Where these overly a crust, the likelihood of triggering is increased.
Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 11th, 2013 2:00PM