Spent the past few days on the Duffey at the Wendy Thompson Hut.
Conditions continued to improve as time went on, although the vigorous warm
storm that smacked the Whistler area did not make it through the blocker into
the basin, which was very good news indeed.
On 091220, Cerise was getting patches of rain according to some
reports, but these did not penetrate into Marriott above the headwall.
Consequently, there was a reasonable amount of lower density storm snow,
accumulating to an average 47cm over the two-and-a-half day storm. From 5500ft
up, this was right-side up for the most part, and the nearest crust to the
surface was normally about 80cm down. Total snowpack in the basin ranged from
240-275cm and everything was quite fully filled-in.
Throughout the majority of the storm, we stayed on low-angled
terrain. Compression tests were giving easy results, with occasional failures
in the storm snow on cutting the blocks. The interface between the initial cold
snow and the rapidly warming second front seemed to be the culprit, and failed
regularly in the first couple of taps to a depth of from 32-28cm down.
Facetted grains over the 091128 crust were stiffening up, but still
responding with good "pops," usually in the "hard" range.
The fact that this layer was down about 74-82cm gave us some concern and we
stayed away from any steeper slopes. Overnight on the 21st, temps dropped to
-15C and the upper snowpack responded by tightening up noticeably. While still
giving sudden planar results on easy compression tests, it was taking
significantly more taps to get results.
There was no change in results on the facets above and below the
091130cr however. Extended column tests on the 22nd were all without results. For
this reason, we did not test steeper slopes.
It is apparent that a widespread cycle ran through the region
mid-week last week when that storm cycle pulled through. Even a few of the
glide avalanches on south-facing slopes at about 7000ft. had failed
catastrophically. Some loose slides in the latter portions of the storm pulled
out slabs to Sz2. With the excellent vis on the 22nd, we were able to see one loose
snow avalanche initiated naturally from steep ground that had caused a slab
failure lower on the slope during the last hours of the storm on the 21st. In
addition, one cornice failure at 7600 had caused a Sz2 when it impacted steep
wind-loaded terrain below.
Skiing quality was quite good on the 22nd, with much-improved vis
and stability and less ski penetration which made for easier tracksetting.
M. Sulkers
ACMG Hiking Guide
Professional member CAA
