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ACMG Mountain Conditions Summary for the Rockies
and Columbia Mountains issued May 1st, 2009.
This is the first ACMG Mountain Conditions Summary
for 2009. The Canadian Avalanche Centre and Glacier National Park published
their last regular avalanche bulletin for the season last week. Banff, Kootenay and Yoho are still publishing bulletins. They
all deserve a pat on the back for doing a fine job over a long, often scary
winter. Our goal is to maintain weekly summaries until the Canadian Avalanche
Centre starts producing regular bulletins again in the fall.
The deep instabilities that caused so many
avalanche involvements and fatalities this winter have ALMOST disappeared. There
will, however, continue to be occasional large,
nasty avalanches stepping down to those layers or to the ground when warm
temperatures finally roll into the mountains or when slopes are subjected to
large triggers such as cornice falls, snowmobiles or big hucks.
Spring has arrived but it has recently had
a cold, cold heart. In the Rockies, the warm temperatures and sunny skies
of mid April warmed and settled the snowpack dramatically. Recent temperatures
as low as -18c and brisk winds in the Rockies alpine have left the snowpack
with a seriously hard surface. Some new snow fell east of the Divide
earlier this week and shallow wintry windslabs were/are a potential problem in
the east slope Alpine and even around Lake Louise. Around the Wapta, Columbia
Icefields and areas west it has been cold, dry and windy and holding an edge was
often the main issue. There was occasionally some corn snow on steep south
facing slopes in the afternoon below treeline but the rest of the world was
rockhard. Travel was fast but ski and boot crampons felt pretty good on even
quite moderate terrain and going for an ugly slide was a serious
possibility.
There have been very limited reports from the
Columbia Mountains. Generally, it sounds like it has been unseasonably cool and
there has been variable amounts of recent storm snow throughout the Columbias
falling on a spring snowpack. Avalanche hazard has predominately been the result
of the wind effect on these sporadic snowfalls and most importantly, the
amount of daytime warming. Again, LARGE avalanches are still a distinct
possibility in the Columbia mountains, especially if we get a dramatic, rapid
warming in the next couple of weeks.
Glacier travel conditions are generally good and
even excellent at the right time and place throughout the Rockies and
Columbias. The shallow early season snowpack and some big early season winds
have however, left some areas with shallow snowbridges. Warm temperatures
are going to weaken the snowpack(especially the thin areas) and make the
crevasse bridges a real problem. I seem to have been touring on the
glaciers with my probe out a lot this spring as I have less faith than
usual in my visual observations of the glacier snowcover.
Snow fell overnight in some locations on the East
slope of the Rockies. Yamnuska had a serious frosting this morning and at noon
it was still white. Also at noon I saw a big wet slough pour off the cliffs to
the climbers right of Goat Buttress and a BIG wet slough pouring down the
gullies right of Guide's Route on the East End of Mt. Rundle. Hard to
believe it will all be gone by saturday as it is only 12 Celsius in Canmore at
noon friday. Could be a poor weekend for those cliffs, the Ghost River area
and for Front Ranges scrambling.
It could be an excellent weekend for low elevation
cragging, corn snow skiing, icefields mountaineering and maybe even some well
timed, fast moving alpine climbing. Get out there and enjoy it but keep an
alert eye out for a rapid or prolonged warming and it's effect on the snowpack,
cornices, crevasse bridges and rock.
Larry Stanier
ACMG/IFMGA Mountain Guide
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