The ACMG had a ski guides training course in Rogers pass for the past week, these were our observations.
Weather
The week started with a warm ridge of high pressure, this brought warm temps, clear skies & freezing levels to 4000m. A temperature inversion meant that we saw temps as high as 12°at 2145m and -10° at valley bottom. These warm temps & clear skies hammered solar aspects. By mid-week the ridge started to weaken giving a cooling trend and the alpine temperature returned to a more seasonable temperature.
Snowpack Structure
An average snow depth of 120cm was found at tree line and 250cm in the alpine. Variable surface conditions were found throughout the week. There is widespread surface hoar to 1800m (as large as size 10 cm), melt freeze crust on all solar aspects, wind effect in the alpine, low density snow on sheltered aspects. A well settled upper pack overlies the Xmas and early season facets. These facet layers still remained our main concern throughout the week. We felt that even though the facets have become much less reactive and well bridge in some locations, that there still remains places were we could trigger this layer.
Avalanche Activity
Other than some sluffing out of steep solar aspects early in the week we saw no new avalanches.
Terrain
Elev. range was 1100-2600m.We stayed away from large overhead slopes, steep solar aspects, shallow rocky areas and convex
features with large consequences. Good skiing was to be found on sheltered slopes ( NW - NE aspects) where the snow was still low density. Also. We
witnessed many skiers skiing quite aggressive terrain, but we were still conservative with our terrain choices due to our concern for the deep persistent week
layer and the consequences if those facets are triggered.
Also of note
Snowpack Structure
An average snow depth of 120cm was found at tree line and 250cm in the alpine. Variable surface conditions were found throughout the week. There is widespread surface hoar to 1800m (as large as size 10 cm), melt freeze crust on all solar aspects, wind effect in the alpine, low density snow on sheltered aspects. A well settled upper pack overlies the Xmas and early season facets. These facet layers still remained our main concern throughout the week. We felt that even though the facets have become much less reactive and well bridge in some locations, that there still remains places were we could trigger this layer.
Avalanche Activity
Other than some sluffing out of steep solar aspects early in the week we saw no new avalanches.
Terrain
Elev. range was 1100-2600m.We stayed away from large overhead slopes, steep solar aspects, shallow rocky areas and convex
features with large consequences. Good skiing was to be found on sheltered slopes ( NW - NE aspects) where the snow was still low density. Also. We
witnessed many skiers skiing quite aggressive terrain, but we were still conservative with our terrain choices due to our concern for the deep persistent week
layer and the consequences if those facets are triggered.
Also of note
We found that lower elevations on glaciers had a variable amount of snow. In some places there was only 35cm of snow on the ice and that most of these areas were quite rotten. We felt the snow bridging over crevasses at these places was quite week and we preceded with more caution. The wide spread surface hoar below 1900m is now also buried by a few cm's and this will be our next major layer to deal with.
ACMG guides
training course.
ACMG guides
training course.