Avalanche Forecast

Issued: Mar 16th, 2012 11:01AM

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.

jfloyer, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Generally settled weather with flurries possible throughout the forecast period, Saturday, Sunday and Monday. Winds generally light, initially from the southeast, becoming southerly on Sunday and Monday. Freezing levels going up to around 800 m during the day and dropping down to valley bottom each night.

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. 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 triggering.

Problems

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

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

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 17th, 2012 9:00AM