Avalanche Forecast

Issued: Feb 12th, 2012 6:27AM

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

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Good - -1

Weather Forecast

Monday: Mainly sunny conditions, with light northerly winds. Freezing level around 1300 m. Tuesday: Sunny in the morning, becoming increasingly cloudy later on with the possibility of some light snow late in the day. Winds backing southwesterly. Freezing level around 900 m. Wednesday: Mostly dry and bright. Freezing level around 800 m.

Avalanche Summary

Isolated, small, wet avalanches were observed on Friday and Saturday in response to moist snow surface conditions. A few very small skier-triggered avalanches were also reported, failing in the top 5-10cm of moist new snow.

Snowpack Summary

Cooler temperatures following rain that fell up to 1700 m has set up a crust at lower elevations. Generally light snowfall has buried an assortment of old snow surfaces including crusts, old wind slabs, surface hoar and surface facets. The crusts formed on all aspects at lower elevations and on steep solar aspects higher up. Old wind slabs were on a variety of aspects behind exposed terrain features. The surface hoar (5-10mm) was most prominent at and above the recent cloud associated with inversion conditions. Friday's moist snowfall may have destroyed this surface hoar in many places. Surface facets have grown particularly on northern aspects where colder temperatures have persisted. In general the snowpack is now well bonded in most locations. A mid-pack layer of concern is a rain crust (buried on Feb 1st) now down 10-40 cm, which exists up to about 2000 m. This may have potential to become reactive with additional snow load in areas where additional crusts do not lie above it, such as north aspects at treeline. Lower layers include a mid-January crust (down 50-100 cm), and a mid-December crust (down up to 200 cm); these now only present concerns in shallow snowpack areas. The average treeline snowpack depth at is around 240cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh snow with moderate SE winds have formed wind slabs in the immediate lee below ridgelines and behind terrain features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 13th, 2012 3:00AM

Login