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Avalanche Forecast

Dec 20th, 2013–Dec 21st, 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.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Very little precipitation in the forecast for this region. Saturday, Sunday, Monday: A chance of flurries each day, with light snow possibly starting to fall Monday afternoon. Treeline temperatures consistent around -10C. Ridgetop winds moderate from the NW, picking up a little on Monday afternoon.

Avalanche Summary

A few loose dry sluffs were observed on Friday. No Slab avalanches were 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. 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. Check out this video of a recent snowpack test on this layer. Despite it's reactivity in snowpack tests, we have not yet seen widespread avalanche activity on this layer. I suspect it only needs a little more additional load to turn this into a more serious avalanche problem. A buried crust from mid-November can be found near the base of the snowpack below 1650 m and is breaking down into facets.

Avalanche Problems

Wind Slabs

Mostly S and SW winds continue to develop wind slabs in the alpine and open areas at treeline.
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

The most significant interface is a layer of surface hoar from early December. This is buried 30-70 cm below the surface and is becoming more reactive in areas where the upper slab has become a little denser.
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: Possible

Expected Size: 1 - 4