Avalanche Forecast

Issued: Feb 11th, 2019 8:01AM

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

Parks Canada Chris Gooliaff, Parks Canada

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Strong winds have created rock-hard slabs in the alpine. Wind slabs are now on the opposite side of the mountains due to the N winds. Beware of triggering slabs from shallow snowpack areas, especially on S-SW aspects.

Summary

Weather Forecast

Sunny with cloudy periods and an alpine high temperature of -17C along with light ridge wind from the NE. Increasing cloud tonight with light flurries. Tuesday's forecast calls for light precipitation along with light SW winds and alpine high of -11C. Wed/Thurs will be mixed sun/cloud with temp's remaining in the mid-minus teen's.

Snowpack Summary

Saturday's strong NE winds have created widespread wind slabs. These lay on a suncrust on S and W alpine aspects. Storm snow has been redistributed and is faceting due to the cold temps. Weak layers of concern, the Jan 31 and Jan 17 interfaces (surface hoar and sun crust), are down ~50cm and ~70cm at tree line.

Avalanche Summary

Natural activity has tapered off with alpine winds dying down. Several natural avalanches sz 2.5 to 3 were observed from N and S aspects on Park One, Smart, and Tupper from previously controlled slopes. No reports of human triggered avalanches yesterday after numerous reports from Saturday during an intense Northerly wind event.

Confidence

Due to the number of field observations

Problems

Wind Slabs

An icon showing Wind Slabs
Strong to extreme NE winds have redistributed storm snow into hard wind slabs and loaded pockets on lee features. On southerly aspects, wind slabs are poorly bonded to a buried crust. These slabs are sensitive to human triggering.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious in shallow snowpack areas where triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs
The Jan 31 and Jan 17 surface hoar layers are down ~50 and ~70cm respectively. These layers exists on all aspects, and are most problematic between 1400-1900m and on steep solar aspects where it overlies a crust.
Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 12th, 2019 8:00AM