Avalanche Forecast

Issued: Apr 14th, 2013 10:15AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain for the entire period

Weather Forecast

A ridge of high pressure is expected to develop throughout the forecast period. A mix of sun and cloud and generally light east/northeast winds are expected each day. Daytime freezing levels are meant to climb gradually from about 1000m on Monday to about 1600m on Wednesday.

Avalanche Summary

No new avalanches have been reported. This is more likely a reflection of a lack of observations, rather than actual conditions. In a region to the south with a similar weather pattern, wind slab avalanches to size 2 occurred at upper elevations in response to snowfall and wind on Friday night.

Snowpack Summary

Generally moderate snow accumulations from Friday night have been shifted by southwest, and more recently northeast winds into windslabs which exist at treeline and above.Some professionals are expressing concern for a surface hoar interface buried within the upper metre or so of the snowpack, mainly on high-elevation northerly aspects. It may be slowly gaining some strength, but these slopes should still be treated with suspicion. On other slopes, recent storm snow overlies a crust. This interface may become particularly reactive on solar aspects as sunnier skies prevail over the next few days. Cornices in the region are very large and potentially destructive. Triggering will become more likely with forecast sunny periods.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent snowfall has been redistributed by changing winds. Wind slabs exist on a variety of aspects at treeline and above. Wind has also formed very large and potentially unstable cornices.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
A layer of surface hoar may be buried about a metre down, mainly on high northerly aspects. A surface avalanche stepping down, cornice fall, or the weight of a person from a thin-spot trigger point could trigger it.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 15th, 2013 2:00PM