Avalanche Forecast

Issued: Mar 14th, 2015 9:35AM

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

Avalanche Canada rbuhler, Avalanche Canada

Tricky storm conditions are expected in the alpine. If you head up high on Sunday, conservative decision making is essential.

Summary

Confidence

Fair

Weather Forecast

On Sunday, a ridge of high pressure should keep the region mainly dry. A mix of sun and cloud is expected with freezing levels around 1000m and light-to-moderate alpine winds from variable directions. On Monday, mainly cloudy conditions are expected with light winds and freezing levels around 1500m. Tuesday should be similar but freezing levels may reach over 2000m.

Avalanche Summary

On Friday, widespread natural activity up to size 3 was reported in parts of the region. This was in response to very warm temperatures and strong sun. These avalanches were mainly in the alpine and were reported on all aspects. However, the largest avalanches were reported from north aspects. Much of this activity was releasing on the mid-February layer down 30-60cm. On Sunday, touchy wind slabs are expected in the alpine and it may still be possible to trigger wet sluffing at lower elevations. There is a still a concern for avalanches to step down to deeply buried weak layers resulting in larger persistent slab avalanches.

Snowpack Summary

At higher elevations, new snow sits over a variety of surfaces including moist snow, crusts, wind affected surfaces, and/or old wind slabs which may still be reactive. Rain has soaked the upper snowpack to around treeline elevation. In the alpine, strong winds during the storm have redistributed the new snow into wind slabs in leeward terrain features. Prior to the storm, 30-60cm of snow was sitting over a weak facet/crust layer that was buried in mid-February. The late-Jan crust/surface hoar layer (over 1m deep) and the mid-January surface hoar (around 1.5m deep) have been dormant for several weeks but now have the potential to wake-up with the current warm temperatures and new storm loading.

Problems

Wind Slabs

An icon showing Wind Slabs
At higher elevations, new snow and strong winds have formed wind slabs. Warm temperatures and an underlying weak layer may increase the likelihood of triggering these wind slabs.
Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
New loading from rain or snow coupled with the persistent warm conditions may overload buried persistent weak layers resulting in very large avalanches.
Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Mar 15th, 2015 2:00PM