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ACMG Mountain Conditions Summary for the Rockies
and Columbia Mountains issued May 8th, 2008.
An upslope snowstorm rolled into the East Slope of
the Rockies today. Heavy snows reported from
the Kananaskis, the David Thompson Country and as far north as
the Maligne Lake road in Jasper. At 2 pm today, National Park wardens
in both Lake Louise and at Sunwapta (south of Jasper) said that snowfall
was just beginning under very low cloud ceilings and the temperatures
were just above freezing. Yuck!
There is probably enough snow that a short term
avalanche hazard exists on previously dry East Slope scrambling peaks like
Yamnuska. My concern would be hikers triggering small avalanches on loaded
slopes and in steep gullies that could have enough mass to knock them
off their feet and drag them over the rocks. It is also likely that there
will be a nasty bit of rockfall and some small wet avalanches if it
clears up and gets warm as forecasted tomorrow and saturday.
Across the snow belts of the East slope and
certainly in the Kananaskis high country, this storm snow will very likely have
fallen on a weak, isothermal snowpack below treeline. In the daytime heat
this weekend it would probably be very wise to avoid skiing avalanche
terrain at and below treeline on the East Slope, unless we get a
suprisingly good freeze one night. At treeline and in the alpine, be very
conscious of the potential for natural and skier triggered slab avalanches,
partially as a result of the new snow load. The new snow is also going
to camouflage lots of rocks and stumps, especially below
treeline.
In the Columbia Mountains and along the divide
of the Rockies there has been less recent precipitation. However, as we said
last week, in the alpine and high treeline areas there is still a winter
snowpack. Isolated large slab avalanches releasing on persistent weak layers
from the winter are still being observed at Rogers Pass and in the Rockies.
Large wet avalanches are also going to continue to be a concern on southerly
slopes and faces for some time yet.
Daytime heating is big part of almost all potential
avalanche and rockfall problems right now so make sure your trip plans involve
being well out of harms way relatively early in the day. Also, make sure you are
getting a real freeze to start your trip. Rain anytime, or a warm grey
night and a hot,sunny morning quickly changes everything. If you are
thinking of backcountry skiing in the Columbia mtns, check out the last regular
avalanche bulletin of the season from Glacier park, issued yesterday.
Classic spring ski mountaineering could be
just round the corner IF we ever get a real ridge of high pressure rolling in.
In the mean time, you can expect a mixture of slush, crusts, powder, windslab,
fresh snow, isothermal snow and bare ground. Over the next week, I
would also assume that the avalanche hazard will be wildly
variable. It will be potentially variable throughout the course of the
day, and certainly will vary across the ranges, across the terrain and
especially at different elevations and on different aspects. Patience is a
virtue and all that kinda stuff.
With this amount of snow, front range multi-pitch
rock routes may need at least a day or two to dry out and the crags at least a
couple of warm sunny hours.
Sunny and forecasted highs of 75 Fahrenheit for the next five days in
Yosemite. I have to include some good news!
Larry Stanier
Mountain Guide
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