RE: The 2011 October Crust.
The October Crust is also alive and performing here in the Rockies, but it
is pretty isolated in spatial distribution. It is only in some locations
above treeline and appears to have melted elsewhere. Also it is very close
to the ground so surface roughness plays a factor.
Here are some avalanches that have failed with October Crust as part of the
failure/bed surface
A natural size 2.5 on Wawa bowl on Nov 24 directly after the storm had a
15cm Knife crust on the ground with 3-6mm DH on top in the upper start zone
but none in the lower start zone or track.
A skier triggered size 3 on Coral 3 on Dec 04 had an older snow surface
that is suspected to be October Crust with DH on top in 1/2 of the upper
start but none in the track.
A skier remote 200m size 2.5 on Observation Peak on Dec 03 appears to have
a smooth crust like bed surface in part of the bed surface that I also
suspect is Oct Cr.
This smooth bed surface in the start zones is likely responsible for some
of the wider and larger propagations of early season avalanches that we
have been seeing. We will have to wait and see how much of a factor it
plays into the future, but it is definitely worth noting and looking for
right now.
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WAWA BOWL Nov 24, 2011
See message # 2 for more photos
Brad White
Visitor Safety Programs Specialist
Banff, Kootenay and Yoho National Parks
PO Box 900 220 Hawk Ave.
Banff, AB T1L 1K2
403-760-0556 (cell)
www.parksmountainsafety.ca
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