Avalanche Forecast

Issued: Feb 12th, 2019 8:00AM

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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Recent strong northerly winds have created hard slabs on S-SW aspects. These sit atop a crust and are reactive to human triggering.

Summary

Weather Forecast

Mainly cloudy with isolated flurries today, alpine high of -12*C, and light SE ridge winds. More of the same tomorrow and Thursday, with sunny periods poking through the cloud and trace snowfall amounts. Alpine high of -12*C and light ridge winds. Friday may bring up to 10cm of snow, light to moderate ridge-top winds, and an alpine high of -9*C.

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. No avalanche activity observed yesterday in the highway corridor. 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
Recent 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 cautious in shallow snowpack areas where triggering is more likely.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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 exist on all aspects and seem most reactive between 1400-1900m, especially on steep solar aspects where they overlie a crust.
Dig down to find and test weak layers before committing to a line.Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 13th, 2019 8:00AM