Went for my first tour in some time to Rogers Pass today – checking out the west facing basin below Mt. Sir Donald.
10cms of fluffy low density snow fell overnight and during the day today – definitely sweetened up the skiing today.
No avalanches observed nor any wind effect up to our high point of 2300m. When I got off of the established skin track in the valley bottom glades(1600m.), we experienced several whumpfs (sound of weak layer collapsing and propogating)– a quick poke in the snow revealed the Dec.10 Surface hoar crystals (10-15mm.) under @30cms of snow which failed when I tried to isolate a block to do a compression test on. Luckily it was really flat here!
Higher up (1900-2200m), I had less whumpfs when breaking trail and test results where correspondingly higher with no fracture across the column when doing an extended column test (ECT) – the surface hoar was in the 5-6mm. size range and was overlying a faceted interface – Still found clean fractures on compression tests (Sudden Planar). Depth of slab over the Dec.10 interface was between 30-50cms., depending on elevation and location.
We stuck to moderately inclined slopes and small terrain features and avoided larger open features (including overhead). I definitely found things lees reactive where there were old ski tracks (and not just a few) – wouldn’t count on this too much when the slab gets thicker in the future.
The fast and silky snow conditions made skiing this moderate angled terrain a real blast.
Probably still a good time to give the larger/steeper features a miss.
Have a great Holiday Season and may Santa bring you lots of powdery turns this winter!
Cheers.
Scott Davis
ACMG/IFMGA Mountain Guide