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Avalanche Forecast

Dec 18th, 2013–Dec 19th, 2013
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: South Rockies.

This forecast is based on limited data. If you are out in the mountains, we would like to hear from you at forecaster@avalanche.ca

Confidence

Poor - Due to the number of field observations

Weather Forecast

An arctic ridge builds on Thursday bringing dry conditions. The next Pacific low pressure system hits the North Coast on Thursday and will reach the southern interior on Friday bringing light precipitation for Friday and Saturday.Thursday: A mix of sun and cloud, treeline temperatures around -15C, light NE winds switching to W as the front approachesFriday: Increasing cloud cover, light snowfall beginning in the afternoon, treeline temperatures around -10C, light westerly windsSaturday: Light snowfall, treeline temperatures around -10C, light SW winds

Avalanche Summary

No new avalanches reported.

Snowpack Summary

There appears to be a lot of snowpack variability across the region.  Snowpack depths at treeline seem to vary from 50 - 110 cm with high variability in wind-exposed areas. There are several persistent weak layers which are still being discussed in the region.  There is a lot of uncertainty as to the reactivity of these layers and it may vary across the region.  We highly recommend digging and investigating these layers in your local area before exposing yourself to avalanche terrain.  Nearest to the surface is the mid-December (~Dec 10) facet/surface hoar/crust interface which does not seem to have enough snow on it yet to create a widespread problem.  Next is the late-November/early-December interface which is made up of surface hoar, a crust, and/or facets.  This layer is typically down 30-70cm and is most likely to pose the biggest problem for the region at the moment.  The mid-November crust is likely in the middle of the snowpack and may be faceting. Near the base of the snowpack is the early-Oct crust/facets and potentially depth hoar which may still have the potential to create avalanche problems, especially in thin snowpack areas. 

Avalanche Problems

Wind Slabs

Wind slabs in the alpine and open areas at treeline remain the primary problem throughout most of the region.
Be cautious as you transition into wind affected terrain.>Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth>

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Persistent Slabs

A variety of PWLs are still being discussed across the region including the Oct crust, the mid-Nov crust, and the early-Dec surface hoar. These layers are generally inactive or stubborn to trigger but may still pose a problem in isolated areas.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Dig down to find and test weak layers before committing to a line.>Avoid shallow snowpack areas on steep, convex terrain where triggering is more likely.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely - Possible

Expected Size: 1 - 4