Mountain conditions to date in the Rockies and Interior July 27, 2005
Since the end of winter, snow conditions in the high alpine have been tricky to
evaluate for alpinists. Following a warm and generally sunny month of May,
above normal precipitation occurred in June. This included heavy rain to
mountaintop during some of the storms as well as significant snowfall events
above 2750 metres.
By early July, this resulted in a layered snowpack with everything from wind
slabs to wet layers to thin melt-freeze crusts. Since July 20, more seasonal
weather and temperatures have started to affect the ranges. Warm daytime
temperatures are beginning to penetrate the upper layers and the odd clear
night has occurred. This has resulted in some crust formation following those
clear nights. These crusts have been short lived however, and without more and
consecutive clear nights, crusts will remain relatively thin and will not last
very long.
The snowpack described above has several potential weak layers deeper in the
snowpack, which are still of concern. Daytime avalanche cycles have been
starting as early as 10 or 11 am and are an indication the deeper weaknesses
will become unstable quickly when warming occurs. With a number of potential
weaknesses in a snowpack, confidence level on steep snow slopes for alpine
routes has been low. For this reason, many alpinists have been avoiding them,
especially when the snow is being warmed by sun or high temperatures and on
days when there is little or no crust formation overnight.
We are still not out of the woods on this one. A decent hot spell and then a
more normal summer pattern of warm days and consecutive clear nights is what is
needed to really get into a normal summer pattern. Such a weather pattern will
promote the formation of hard neve (consolidated summer snow with no
significant layers) which provides good snow climbing conditions.
Below about 3000 metres, dry summer conditions are present.
An update on current conditions will be provided July 30, 2005.
this summary prepared by: ML, LS, KK
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