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Avalanche Canada bcorrigan, Avalanche Canada

South Rockies Avalanche Forecast

Feb 24th, 2016 8:20AM

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

Solar input and rising freezing levels may push the danger higher than forecast. Make conservative terrain choices and avoid slopes that might be affected by a cornice failure.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Friday

Weather Forecast

The high pressure ridge remains firmly in place for the next 2 days. Mostly clear skies with the possibility of high cirrus in advance of the next Pacific frontal system scheduled to arrive in the area on Saturday. Although there is some disagreement in the forecast models, freezing levels are forecast to go above 1500 metres and some models are pushing the freezing level to 3000 metres. Winds are forecast to be light to moderate from the south-southwest.

Avalanche Summary

Cornice failures are highlighted from yesterday, triggering size 2.5 to size 3 avalanches. On the eastern slopes there were no reports of avalanches.

Snowpack Summary

Wind slabs have formed in lee terrain at treeline and above. A melt freeze crust which formed during the 2nd week of February has been recently reported between 20 and 45 cm, and may be more deeply buried in the south of the region. This crust layer has also been reported with surface hoar and facets in some places, and is definitely a layer to keep in mind. East of the divide wind slabs should be on your radar. Wind transported snow has also encouraged new cornice growth. These cornices are reported to be huge and unsupported. With warm weather and sun in the afternoon, these could become a significant hazard.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely

Expected Size

1 - 3
Wind slabs are still lurking at tree line and above.
Be careful with wind loaded pockets on steep slopes below ridge crests.>Avoid cross loaded slopes at or above treeline.>

Aspects:

North, North East, East, South East, South.

Elevations:

Alpine, Treeline.

Cornices

An icon showing Cornices

Likelihood

Likely - Possible

Expected Size

1 - 4
Cornices are becoming large and fragile with warming temperatures. A cornice failure might trigger deeply burried instabilities and produce a large and destructive avalanche.
Cornices become weak with daytime heating. >Give cornices a wide berth when travelling on or below ridges.>Extra caution needed around cornices with current conditions.>

Aspects:

North, North East, East, South East.

Elevations:

Alpine, Treeline.

Valid until: Feb 25th, 2016 2:00PM