Avalanche Forecast

Issued: Mar 31st, 2012 10:47AM

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

jlammers, Avalanche Canada

Sea To Sky.

Summary

Confidence

Good

Weather Forecast

Sunday: a mix of sun and cloud with light snowfall becoming heavy overnight - moderate southwest winds - freezing level at 850m Monday: heavy snowfall continuing overnight - strong to extreme southwest winds - freezing level between 1000 and 1500m Tuesday: light snowfall with possible clearing - moderate southwest winds - freezing level at 700m

Avalanche Summary

Explosives control on Saturday produced numerous size 1.5-2 avalanches that ran on the March 26th interface. Some of these avalanches ran sympathetically with other slides, or remotely at distances of up to 300m.

Snowpack Summary

The latest pulse of precipitation brings the storm snow totals to between 75-100cm overlying surfaces that were buried on March 26. This interface consists of a crust which exists on all aspects except true north facing slopes at treeline and in the alpine, where small surface hoar is present in sheltered places . This week's snow continues to be redistributed by consistently moderate to strong variable winds, forming windslabs in unsuspecting locations. Cornices are huge, and will continue to grow with this weather pattern. Below the March 26 interface, last week's storm snow is well settled and bonded, with further strength gains deeper in the pack. In isolated locations the weaknesses from early February linger and the chance for a large, deep release is possible in times of rapid loading from new snowfall, rain or cornice fall.

Problems

Storm Slabs

Recent storm snow will continue to be reactive, especially where it overlies weak layers buried on March 26th. Solar radiation may also trigger storm snow as a slab or as a loose snow avalanche.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 5

Wind Slabs

Consistent moderate to strong winds have built hard windslabs in the alpine/upper treeline and soft slabs below. These overlie the slick melt freeze crust and spotty surface hoar.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Cornices

Cornices are very large and may become more fragile with the increased load, wind or warm temperatures.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 6

Valid until: Apr 1st, 2012 9:00AM