Avalanche Forecast

Issued: Mar 17th, 2012 10:08AM

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

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Flurries are expected Sunday, Monday is more likely to be dry. Sunny breaks for both days, freezing level around 500 m. Winds light to moderate southerly. Similar weather expected for Tuesday morning, although winds may ramp up from the south building for a frontal system expected to bring snow Tuesday afternoon.

Avalanche Summary

Soft slabs were reported to have been developing at treeline on Thursday. Some activity was noted outside the region to the west in recent storm snow on Friday. Nothing has been noted from this region. However, observations have been very limited.

Snowpack Summary

Moderate amounts of low density snow sit over a variety of old surfaces that include widely distributed hard wind slabs, or melt freeze crusts that exist on most aspects below 1000m and on solar aspects as high as 1600m. In exposed areas the newer snow has been shifted into deeper pockets of soft wind slab. The mid February persistent weak layer interface, comprised of spotty surface hoar, facets and crusts, is buried 80-120 cm below the surface. No recent activity has been reported on this interface. However, recent snowpack tests have been giving hard but sudden "pop" results and indicate it is has the potential to react given the right trigger in the right place. For route selection, it should still be on your radar and is most likely triggerable on steeper, unsupported terrain. Cornices in the area are reported to be very large and primed for natural collapse or triggering by a person.

Problems

Wind Slabs

An icon showing Wind Slabs
Recently formed windslabs may exist on lee slopes adding to a strengthening hard wind slab problem that developed last week.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

An icon showing Cornices
Large cornices exist in alpine terrain. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
The likelihood of triggering persistent layers buried in early February is greatest on steep, unsupported terrain . Although no recent avalanches have been reported, the chances of triggering may increase with solar radiation forecast for the weekend

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 18th, 2012 9:00AM