Avalanche Forecast

Issued: Mar 1st, 2014 8:23AM

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

triley, Avalanche Canada

Sea To Sky.

Forecast new snow and strong winds are expected to develop a new storm slab over the next few days. The buried weak layer from early February continues to be a concern. Check out the forecasters’ blog.

Summary

Confidence

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

Weather Forecast

Overnight and Sunday: 5-10 cm of snow overnight combined with strong Southwest winds and freezing levels near valley bottoms. Another 10-20 cm of snow combined with strong Southwest winds and freezing levels rising to about 1000 metres.Monday: 5-10 cm of snow in the morning with strong Southwest winds. Some periods of broken clouds in the afternoon. Freezing levels at about 1000 metres.Tuesday: More snow and Southwest wind with freezing levels rising up to about 1500 metres.

Avalanche Summary

No new reports of avalanche activity since the cold air moved into the region. While natural activity has subsided on Northerly aspects in the region, human triggering with the possibility of long fracture propagations continues to be a concern.

Snowpack Summary

Cold arctic air has invaded the region creating a melt-freeze crust on all aspects at treeline and below, and on all but North aspects in the alpine. The recent very warm alpine temperatures and strong solar radiation caused a great deal of settlement in the old storm slab above the early February weak layer. The February weak layer of crusts and facets has been reported to be rounding and bonding in areas where the old storm slab is 150 cm or deeper. Shallow snow pack areas where the old storm slab is closer to a metre or less continue to give sudden planar shears in snow profile tests. North aspects in the alpine may have had enough warming to settle the storm snow into a cohesive slab, but not enough to improve the weak layer bond. Big un-supported alpine North aspects are the most likely place to find a well preserved deeply buried February weak layer that may continue to allow for long propagations resulting in very large avalanches.

Problems

Persistent Slabs

Human triggering with the possibility of long fracture propagation resulting in very large avalanches continues to be a concern. North aspects in the alpine may be the most suspect slopes.

Use conservative route selection, stick to moderate angled terrain with low consequence.>Stick to simple terrain and be aware of what is above you at all times.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Storm Slabs

Forecast new snow and wind are expected to develop a new storm slab that may not bond well to the mix of old surfaces.

Minimize exposure during periods of heavy loading from new snow, wind.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 2nd, 2014 2:00PM