Avalanche Forecast

Issued: Jan 20th, 2012 9:26AM

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

jfloyer, Avalanche Canada

South Coast.

If the storm Friday night drops 25 cm or more new snow, consider all elevations to be at high danger.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Friday night: 10-15 cm new snow with strong to extreme SW ridgetop winds.Saturday: Approximately 10 cm new snow with strong winds veering westerly. Freezing level staying at valley bottom in most areas.Sunday: Another winter storm bringing around 10-15 cm additional snow late in the day and strong winds. Freezing levels remaining at valley bottom.Monday: Further snowfall likely, with heavy pulses possible in localized areas. Strong SW winds. Freezing levels remaining at valley bottom.

Avalanche Summary

Loose snow activity was observed on Thursday. Observations on Friday were limited to Treeline and below and there were no reports of slab avalanches. If new snow amounts exceed 25 cm by Saturday, I anticipate a significant avalanche cycle will occur in this region.

Snowpack Summary

Dense new snow is setting up a fresh storm slab on top of the previous cold, low density snow from the last few days. This cold, low density snow will very likely act as a weak layer, enhancing the potential for slab avalanches to run. A rain crust lies buried around 45cm below the surface up to around 1900 m. The bond at this crust is reported to be quite good. However, on steep slopes, this interface could still act as a good sliding surface. Weak layers lower in the snowpack have generally ceased to be of concern, except perhaps in thin rocky areas.

Problems

Storm Slabs

New dense storm snow will fall on existing cold, low density surfaces. This will create a highly unstable upper snowpack with a high potential for slab avalanche activity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Wind Slabs

New snow and strong winds will set up touchy new wind slabs.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Jan 21st, 2012 8:00AM