Today (Jan 7) I spent the day with several RAC instructors doing a
training session. We went up towards Bow Hut just into the moraines
towards the Little Crowfoot Glacier.
At the parking lot it was scattered cloud, -8, 17 cm of storm snow from
the previous couple of days, light NW winds at ridgetop with signs of
previous significant wind transport at upper elevations. There was a
suspicious lack of avalanche activity.
There were several whumpfs noted heading up the trail, with one causing
cracking on adjacent slopes as we entered the canyon. Further up the
canyon one of the group stepped off the packed trail and propagated a
size 1 slab above, 20-30 cm deep, 7 m wide and running 15 m downslope
(photo). It was a storm snow slab with the failure layer being facets
lying on the ground.
We noted another larger size 1 in the moraines above our high point,
possibly remotely triggered by another party in the vicinity. It
occurred while we were digging a test profile (at treeline on a north
aspect).
In the profile there were no surprises: 40 cm of a variety of grains, 4
finger strength, lie atop 75 cm of facets and depth hoar, fist to 1
finger strength. Easy to moderate resistant planar shears at the storm
snow interface, hard sudden planar shears on the facets.
On return to the parking lot, on the west face of Observation Peak, we
saw a skier triggered size 1 which seemed to have remotely triggered a
large size 2.
Alpine: Considerable, Treeline: Considerable, Below Treeline:
Considerable where there is enough snow to overcome the ground
roughness, Low elsewhere. We seem to be just reaching threshold depths
below treeline now.
Confidence is low and consequences high; there are lots of rocks to hit
as you get dragged down by the swirling white vortex. Keep your head up
and your feet on the ground
Mark Klassen
Mountain Guide
mark@xxxxxxxxxxxx
www.alpinism.com.
P1070036.JPG
|