Avalanche Forecast

Issued: Jan 19th, 2015 4:39PM

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

Avalanche Canada ian jackson, Avalanche Canada

Parks Canada is planning Avalanche Control on Mt. Dennis for Tuesday January 20. No ice climbing or travel in this area please. TH

Summary

Weather Forecast

Temperatures should cool, and skies should clear as the winds shift to the NW Tuesday under the influence of a high pressure system. A series of lows will be pushed well North as a result of this high but clouds should return mid day Wednesday with increasing winds, a chance of light snow arriving overnight, and temperatures rising into Thursday.

Snowpack Summary

15 to 25cm of recent snow with west winds has created slabs on facets, surface hoar, sun crust on steep South slopes and hard windslabs along ridge crests Treeline and above. The Dec 18 surface hoar layer is down 50 to 60 cm. This layer is very prominent and has been producing moderate test results and whumpfing on past field trips.

Avalanche Summary

On an avalanche control flight today to the Sunshine road, 8 of 9 shots produced significant avalanches and 3 natural avalanches were observed. Most of these initiated in the recent storm slabs 20 cm deep but several also stepped down to the Dec 18 interface to a depth of 50cm. Two size 1.5 naturals were observed on Labbat's Lane and Pilsner Pillar

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

An icon showing Wind Slabs

New windslabs 20 to 40cm deep can be found in almost any lee areas including crossloaded features. These slabs are easily triggered and some the resulting avalanches have been stepping down to the Dec 18 persistent slabs.

  • Be cautious as you transition into wind affected terrain.
  • If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A persistent weak layer from Dec 18th of surface hoar/crust/facets lurks 50-60 cm's below the surface. This layer is most reactive at the tree line elevation where it is a surface hoar/crust combination.

  • Choose conservative lines and watch for clues of instability.
  • Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Jan 20th, 2015 4:39PM