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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