Avalanche Forecast

Issued: Dec 28th, 2013 8:12AM

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

Parks Canada catherine brown, Parks Canada

It is a good day to make conservative terrain choices. Give recent storm snow a chance to settle and stabilize before considering bigger objectives.

Summary

Weather Forecast

A ridge of high pressure will build over the region today.  Precipitation will be light, and west ridge-top winds, 15km/h.  Freezing levels will remain at valley bottom. Light precip will continue Sunday and Monday, with temperatures rising and freezing levels forecast to rise to 1500 m on Monday.

Snowpack Summary

~60cm storm slab sits on a weak layer of large snowflakes which are reactive in tests. The Dec 8 PWL, which is surface hoar at lower elevations and facets and variable wind slabs at higher elevations, is down ~80cm. The Nov 28 surface hoar, down ~1m. Both layers are showing variable reactivity in snowpack tests.

Avalanche Summary

We have observed natural avalanche activity in the highway corridor in the last 24 hrs. Avalanches are running up to size 3.0 in the storm snow and depositing snow in runnouts. On-going artillery avalanche control is producing few results west of the summit, with results up to size 2.0.

Confidence

Due to the number and quality of field observations

Problems

Storm Slabs

An icon showing Storm Slabs
60cm of storm snow is likely to be triggered by riders. Use caution in steep, unsupported terrain.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Recent moderate/strong SW winds have loaded lee features at treeline and in the alpine. Stay off wind loaded areas until the slope has had a chance to stabilize.
Minimize overhead exposure during periods of heavy loading from new snow, wind.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Weak layers are buried down 80 to 100 cm. In a shallow snowpack where the weak layer is well-preserved, a skier could fail these layers.
Dig down to find and test weak layers before committing to a line.Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 29th, 2013 8:00AM