Report 4, 10/12/10
A short sharp thaw
Hi All,
The last major snowfall in Strathspey was now well over a week ago. We’ve had very little of the snow that hit Edinburgh and Glasgow causing the chaos further south. Most roads have been passable with care through the last week and now with the thaw all the major and well used roads are now generally clear. Minor road are now getting cleared as well.
Here in Boat of Garten (230m) , Wednesday morning started at a crisp -10 deg C but throughout the day there was a steady rise in temperature. By dusk it was just below freezing point and seemed to maintain this level through the night until dawn. It there upon rose to a balmy 6 deg C around noon with the corresponding temperature on the summit of Cairngorm (1245m) rising to freezing point. At 10pm Thursday it had dropped to -1 with a +3 for here in Boat of Garten.
Due to the general depth & temperature of the snowpack on the mountain, I would suggest that to this point all this strong thaw has done is moisten the surface layers of snow. Within the snowpack the temperature will still be well below freezing. This morning (Fri) the mountain webcams seemed to confirm this. The temperature has again risen to 6 deg here in Boat and is now at 1 deg C on the summit of Cairngorm. Many of the snow fences in the ski area are completely buried with the snow depth being what you would expect for the end of a good season, not the beginning. The view from Loch Morlich is of blanket white mountains.
The thaw is due to continue through to the end of Saturday until the high pressure (that’s drawing the warm air over it’s northern flank) becomes more centered over Scotland. Winds will drop and the charts are pointing to a fine day for Sunday and beyond with the 900m temperature dropping back down to -1. Although Britain will be covered by relatively mild air, the radiated heat loss due to the high pressure should see frosts by night and the temperature remain below freezing in the shade by day at least – hence the comment “little thaw overall where snow still lies” on the MWIS forecast.
There may be loss of any rime ice from cliffs and snow cover where the pack is thin but it should be good for the long term with predictions indicating a return to persistently cold conditions next week.
SAIS are presently doing avalanche forecast for the weekends until they kick-off in earnest in mid December.
That’s all for now. Enjoy the winter hills.
Regards,
Andy
Andrew Bateman
Director
Mountain Innovations
