Hoping this finds Everyone keeping well and enjoying the sunny weather.
I took the opportunity to turn the legs over yesterday and have a look at conditions in the Spearhead Range. I went up and over the East Col, down into the Circle Glacier Basin, over to and up Decker Glacier, and out via the broad Disease Ridge/Decker col.
There was a good overnight freeze that set things up for Thursday morning. Though, with the current lift status and uploading times, it's a hint more challenging getting out to the good 'corn' snow to make the timing work. By midday, the temperature was plus 5* in the higher alpine and all snow surfaces were becoming quite soft. By mid-afternoon, the snow surface on high north aspects had become a little spongy and moist - but skiable. A thin but supportive crust is currently buried 5-10cm+ below the snow surface on these high north aspects and the snow below that is moist.
I did notice numerous recent and old natural avalanches. There were many size 1 loose-snow avalanches that have been releasing from below rocky features on all aspects.
The slab avalanches that I did note varied from size 1 to 2 and seemed to average approximately 20-30cm in depth. Some were triggered by cornice fall, others naturally, and at least one I suspected might have been skier-triggered.
The massive cornice that lives on the north-west face of Decker Mountain performed recently and ran into the terrain trap on the south side of the morraine that helps shelter the exit out of that area. Some of the debris was able to overrun the spine of that morraine. Another natural cornice fall off of Overlord Mountain and onto the north-face/glacier was also sizeable.
Here are some characteristics that, either individually or collectively, were associated with the recent activity:
* northerly aspects (lee)
* steep
* 'unsupported' (slope continuity abruptly terminates, for ex. in cliff bands)
* large overhead trigger
Caution on any sun-baked slopes, especially ones that are shallow, steep, and 'peppered' with rocks. Temperatures that, for a measurable amount of time, drop below zero overnight help to 'lock' the snowcover in place again until sun-effect or warmer air tempertaure heat things back up.
Measuring the quality of any overnight freeze is a prudent thing to consider/investigate during the 'freeze-thaw' cycles of Spring. How deeply have cooler overnight temperatures penetrated the snowpack, if at all? How will this affect your route planning/timing/exposure/skiing quality? Good things to ponder.
Cornices continue to be one of the most significant hazards out there right now. Give them lots of respect; they're weakening, large and dense, debris can travel far, and their weight can be a potent trigger for underlying slopes.
There's still a lot of snow in the mountains right now and the coverage is good. I hope this finds each of you in the high places, happy and healthy, and in pursuit of some grand Spring skiing.....
Best regards,
Dale Marcoux
ACMG Ski Guide
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