Avalanche Forecast

Issued: Dec 26th, 2014 8:05AM

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

ghelgeson, Avalanche Canada

South Rockies.

Jump over to avalanche.ca/blogs to learn more about the persistent slab problem.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: Light precipitation is possible Saturday afternoon as a weak system passes over the SE portion of the province. On Sunday a strengthening ridge of high pressure drives cold and dry conditions that will likely persist for the next week. Saturday: Freezing Level: Valley Bottom; Precipitation: 1-3mm | 1-4cm; Wind: Treeline: Moderate, W/SW | Ridgetop: Strong, NW.Sunday: Freezing Level: Valley Bottom; Precipitation: Trace; Wind: Treeline: Moderate NE | Ridgetop: Moderate, NE.Monday: Freezing Level: Valley Bottom; Precipitation: Trace; Wind: Treeline: Moderate, NE | Ridgetop: Moderate, E.

Avalanche Summary

No new avalanche activity to report, but in the neighboring Lizard Range avalanches continue to be human triggered to size 2. If you have any avalanche observations to report, please send an email to forecaster@avalanche.ca.

Snowpack Summary

Prior to Tuesday nights 15 - 20 cm, generally light amounts of snow have fallen in the last week. In the alpine, winds have been conducive to blowing this snow into wind slabs in exposed lee areas. 30 - 60 cm below the surface (more in wind affected areas) you are likely to find a crust that may have surface hoar on top of it. The crust is reported to extend into the alpine to at least 2100 m; the surface hoar was reported to be most reactive on shady aspects around treeline and just below, between around 1600 m and 1900 m. Where the crust exists, it is effectively bridging triggers from penetrating to deeper persistent weaknesses that formed earlier in the season. However, on high alpine slopes above where the rain crust formed, facets, and/or buried surface hoar may be susceptible to triggers.

Problems

Persistent Slabs

New snow from the previous week is coalescing into a slab that rests on a stout crust. In some places a very weak layer of surface hoar may rest between the crust and the slab which is a prime setup for human triggered avalanches.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Stick to simple well supported terrain without convexities and be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Wind Slabs

Watch for stiffening wind slabs in wind exposed terrain at and above treeline. Wind slab avalanches in motion could step down to the mid December crust creating large avalanches.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 27th, 2014 2:00PM