Avalanche Forecast

Issued: Mar 1st, 2014 8:27AM

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.

Avalanche Canada triley, Avalanche Canada

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 avalanche activity reported since the cold arctic air moved into the region. Deep releases on the February layer are most likely to continue from North aspects in the alpine where shaded slopes have not settled and bonded and the weak layer is well preserved.

Snowpack Summary

Cold air that moved down from the arctic has developed a melt-freeze crust on all aspects at lower elevations, and on all but Northerly aspects in the alpine. Recent very warm temperatures and periods of very 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 200 cm or deeper ( there is between 2-3 metres of snow above the weak layer in the Coquihalla area). 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 ( there is about 60-80 cm above the weak layer in the Duffey Lake area). 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

An icon showing Persistent Slabs
Human triggering with long fracture propagation resulting in very large avalanches continues to be a concern. North aspects in the alpine are the most likely slopes to have a well preserved weak layer with a cohesive slab above.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>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

2 - 5

Storm Slabs

An icon showing Storm Slabs
Forecast new snow and wind are expected to develop a new storm slab that may not bond well to the old surfaces.
Minimize exposure during periods of heavy loading from new snow, wind.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

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