Although morning temperatures were cold today in the shade we experienced some
significant sluffing in the Aemmer couloir this morning, likely from sun
affected slopes high above the route.
The temperature was -10 in Paradise valley in the morning and -8 in the couloir
itself at 10am. A significant loose snow avalanche came down at this time and
washed over the party below us. A smaller avalanche knocked two members of the
party above off their feet several minutes later and swept them ~200m down the
couloir.
I suspect that sun exposed NE facing slopes above the upper couloir was the
culprit. This slope isn't visible from the usual Lake Annette approach, nor
from the couloir itself, see attached photo.
Recent storm snow amounts were also higher than forecast in lee area in the
alpine. Valley bottom accumulations were 5-10cm, as forecast. In the alpine
there was 15-30cm of new snow in sheltered areas and up to 70cm in lee areas
such as the couloir itself.
Solar radiation felt intense by 10am, even in areas oblique to the sun, with a
strong sun-shade temperature differential.
Due to the sun exposure of the higher hidden slopes affecting the couloir I
will be moving my start time for that route considerably earlier for clear days
.
---
Josh Briggs
Consulting Geologist / IFMGA Mountain Guide
✆ 403.609.9153
www.briggsconsulting.ca
---
Josh Briggs
Consulting Geologist / IFMGA Mountain Guide
✆ 403.609.9153
www.briggsconsulting.ca
_______________________________________________
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continuity. Conditions differ greatly over time and space due to the variable
nature of mountain weather and terrain. Application of this information
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Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.
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