[MCR] Summary of conditions July 27

Subject: [MCR] Summary of conditions July 27
Date: Thu, 28 Jul 2005 21:17:55 -0700
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