Avalanche: Summit

Location: Colorado

Route & General Observations

Colorado to 2300′

Avalanche Details
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Trigger NaturalRemote Trigger Unknown
Avalanche Type GlideAspect Unknown
ElevationunknownSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

2 recent glide avalanches:
one on a SSW aspect of Wilson South at ~2900' (pictured below)
one below the top of Manitoba on a SSW aspect around ~2500' (closer to the road than the previously observed small crown from the holiday avalanche cycle).

Numerous other glide cracks could be seen on southerly aspect slopes on the eastern side of the road looking up valley, generally all in the mid-elevation band.

Small older crowns/debris below Colorado ridgelines (see picture below), likely occurring at the storm interface during the holiday storm/winds.

Weather & Snow Characteristics
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Clear and COLD in the 'toba lot, well below zero.
Temps increased to single digits at treeline.
Occasional variable light winds.

Snow surface

3-6mm surface hoar along our entire route, always sitting on several inches of soft snow where we traveled below treeline. Above treeline, winds clearly moved a great deal of snow during the last storm... if the surface hoar can also be found above treeline, it may well be sitting on some harder surfaces. Ski penetration of 3-6", with the surface composed of faceting snow that gradually gets firmer (see pit structure below)!


Dug at a wind protected location near treeline, adjacent to where I dug two weeks prior to take a look specifically at the Thanksgiving Crust. At this location, the Thanksgiving Crust is now 80cm deep, and it has a very similar structure and appearance in the pit wall as it did two weeks ago. The only noticeable change was that the facets - located below the crust - appeared slightly larger today, now generally 1mm in size. While CT and ECT tests did not produce failures, a PST failed at 35/100 END, with just a slightly longer cut than observed on 12/16 (30/100 END on that day).

In addition, a layer of recently buried surface hoar was visible in the pit wall 30cm down, at what looked to be the holiday storm interface. This BSH was 4mm in size, and was fairly stubborn in stability test results, with no propagation in an ECT.

Photos & Video
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