Avalanche Forecast

Issued: Jan 11th, 2014 8:09AM

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

catherine brown, Parks Canada

Glacier.

The Park is under an intense storm this morning. Expect a widespread avalanche cycle when the winds increase later today.

Summary

Weather Forecast

A southwest flow is bringing warm air and heavy precip to the park today. Periods of snow are forecast today with 15 cm of snow forecast today, and 10 cm more tonight. Expect ridge top winds around 35 km/h from the SW, gusting to 90km/h today and freezing levels rising to 1100m. Snow continues on Sunday and Monday with elevated freezing levels.

Snowpack Summary

High density new snow is rapidly loading previous lower density layers resulting in a touchy surface slab. At valley bottom, a fast shear layer down 35cm is resulting in avalanches, even below treeline. At treeline this layer is expected to be 50cm deep. The Nov 28th surface hoar may be reactivated by the rapid loading or step down avalanches.

Avalanche Summary

Numerous natural avalanches were observed along the highway corridor yesterday on all aspects, running in the storm snow. Most avalanches were sized 1.5 to 2.5, with 4 sized 3.0. A field team yesterday triggered a size 1.0 avalanche at 2000m, east aspect. Obs are limited this morning, however it seems that several events have run to valley bottom.

Confidence

Problems

Storm Slabs

60 to 70cm of storm snow has fallen over the past 3 days with strong southerly winds. Heavy density snowfall is rapidly loading a previous layer of low density snow causing storm slab formation.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 3

Wind Slabs

Strong southerly winds created touchy wind slabs on lee slopes yesterday. Expect further wind slab development today as the winds pick up this afternoon.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The current rapid loading event could reawaken the deep slab that has been sleeping for the past week.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 12th, 2014 8:00AM