Avalanche Forecast

Issued: Feb 8th, 2012 9:37AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Thursday: A stronger front approaches the coast bringing light-moderate precipitation. Snow amounts 5-10cm. Ridgetop winds 15-25km/hr from the SW. Freezing levels 1300m cooling overnight. Friday: Snow amounts up to 10cms. Ridgetop winds 30-40km/hr from the SW. Freezing levels near 1500m. Saturday a weak ridge of high pressure will bring limited precipitation, alpine sun, and low level clouds. Freezing levels near 1400m.

Avalanche Summary

A report of one natural cornice fall, pulling out a size 3 slab avalanche from the slope below. The avalanche occurred on a North aspect @ 1800m. The crown depth was up to 1.5 m, running 800m.

Snowpack Summary

Surface snow conditions consist mainly of crusts that have developed due to melt/freeze conditions, and direct solar impact on steep Southerly aspects. Northerly aspects still host dry, wintery snow. On exposed lee slopes in the alpine there are pencil-4 finger stiff wind slabs. Surface faceting is occurring on sheltered, shady aspects. While shallow, rocky slopes are faceting and weaker; posing a threat to deeper releases. Surface hoar growth is near 5mm at treeline, and below treeline. These may be our next layers of concern once buried. The Feb 01 (120201) rain crust is down 10-40 cm up to about 2000 meters. The mid-January crust is down between 50-100 cm, and the mid December crust is buried down up to 200 cm. The average snowpack depth at 1650m is near 240cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Changing wind directions may have have formed wind slabs on most aspects, behind terrain breaks in the alpine and at treeline.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 4

Cornices

An icon showing Cornices
Cornices may become weak with daytime warming, and solar radiation. Cornice fall may trigger slabs on the slopes below. Give cornices a wide berth when traveling on ridgetop, or on slopes below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Valid until: Feb 9th, 2012 3:00AM