Avalanche Forecast

Issued: Nov 27th, 2013 7:25AM

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

Avalanche Canada triley, Avalanche Canada

Early season forecasts are based on limited observations. I have removed the danger rating below treeline to reflect the snowpack at this elevation being below the threshold to produce avalanches.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Overnight and Thursday: Light Southwest winds and no precipitation overnight. Some very light precipitation starting early in the morning should bring 2-4 mm during the day combined with increasing Westerly winds.Friday: Very light precipitation and moderate Westerly winds. Freezing levels should drop down to valley bottoms.Saturday: 5-10 mm of precipitation with light Southwest winds and freezing levels about 1000 metres.

Avalanche Summary

No new avalanches have been reported. However, isolated large slab avalanches may still be rider triggered, especially in areas that did not previously avalanche.

Snowpack Summary

Forecast light snow falls may bury the surface hoar that has grown this week, and the new melt/freeze crusts that have developed on steep solar aspects. Snowpack depths at treeline elevations are about a metre, with some wind loaded pockets reported to be near 2 metres deep. There is a new layer of surface hoar sitting above the settling recent storm snow, on southerly aspects there may be a new melt/freeze crust on the surface. The snow from last week has settled and foot penetration is reported to be about 30 cm deep. A buried surface hoar layer may exist 60-120 cm down but seems to be spotty, and drainage specific. Deeper in the snowpack near the base is a melt-freeze / rain crust that formed in October. This is generally found from 80-160 cm down near the base of the snowpack. This layer was reported to be down about 90 cm and "a hard ice crust" on the West slope of the Caribous near Wells Gray Park. Snow pack depths are low for this time of year, with snow pillow data showing that most areas are below average and some are near minimum since data has been collected.

Problems

Persistent Slabs

An icon showing Persistent Slabs
This weak layer deserves our attention. Lets keep this one in the front of our minds as the dry weather pattern breaks down and more load begins to be added to the snowpack.
Be aware of the potential for large, deep avalanches due to the presence of a buried crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Nov 28th, 2013 2:00PM

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