I went for an observation flight around the coast today to assess the
avalanche hazard at a couple of operations. If I use Tim's report from Sun God as a base for the height of snow I can extrapolate the following.
There is over 200cm of snow above 6000' in the Squamish area, but quickly decreases to almost nothing at 900m elevation. Flying north this snowpack decreases to around 120-140cm at 2000m in the Dickson Range north of Dowton Lake. There is about 30cm of snow at 1200m in that area and snow as low as 800m. There was enough coverage that people were skiing in many areas along the Duffy lake road, but there were many crevasses open and lots of newly covered slots apparent by the sags. It appeared that there was lots of wind earlier in the month but recent snow was relatively undisturbed.
The Nahatlach and Stein had about a meter of snow at 2000m and almost nothing below 1200m. Stave and Pitt lakes area had a lot of snow up high (>200cm) but only a dusting below 1200m.
We saw numerous recent avalanches on all aspects in all areas above about the 5000' level. In most cases they were isolate to features that were crossloaded in early November storms or areas with very low surface rougness like glaciers. This recent avalanche cycle was up to size 2.5, and slides were becoming much less frequent with only 3 slides that had occurred in the previous 24 hours. These slides were 40-60cm deep and didn't propogate very far. No slides were observed that started below the alpine.
There was also evidence of an earlier avalanche cycle with debris covered with up to 40cm of new snow. Some avalanches in this cycle were up to Sz3. We only observed one slide that ran the full path to valley bottom.
Surface hoar was sparkling everywhere.
There is lots of ice forming in all the usual areas, but it doesn't quite look fat enough to climb yet.
conny amelunxen
mg
Date: Sun, 25 Nov 2012 20:11:13 -0800
To: coastalex@xxxxxxxxxxxxxx
CC: mcr@xxxxxxxxxxxxxx
From: mcr@xxxxxxxxxxxxxx
Subject: [MCR] Sun God Peak near Birkenhead Lake
We skied N aspect of Sun God on Sunday under sunny skies. There had been a natural cycle on N aspects to size 2.5 possibly 3 in the HST. I could not tell whether the largest slab released on a deeper layer rather than the most recent HST as it was too far away but had impressive propagation. The rapid load released from many start zones but snow felt well bonded where we skied perhaps influenced by the days cool temperatures.
There was 80 cm HS at 4000' and many alders. A test profile at 6000' showed 160 cm HS with a well settled mid pack under the top 40cm low density snow. There was no shears in the HST and only a CTH resistant planar shear on the early November rain crust which is down 130cm. Perhaps the dense mid pack is acting as a sufficient bridge however the bottom 30 cm under the crust is all large facets of little density. We attempted to avoid any shallow or unsupported rocky features because of the weak basal layer and experienced very good skiing top to bottom.
Tim Pochay
Mountain Guide
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