Creep and glide cracks
23rd March 2016
Glide cracks (tension fractures) appearing at the snow surface due to the slow creep of the
snowpack on the bed surface (smooth slopes of grass or rock), cracks may be deep and âcrevasseâ
Avalanche release is unpredictable, avalanche activity may occur when the first cracks appear,
several days or weeks later, or not release at all. Avalanches have the potential to be large and
The observant Â may have noticedÂ theÂ recent addition in our reports of theÂ above icon Â – andÂ also the somewhatÂ ‘opt out clause’ concerning Â predictability!
As such the university educated amongst you may question the wisdom of poking such features with aÂ proverbial big stick – with that in mind I had a quick tour about these last couple of days…….
Unfortunately not – however something like a lowering of freezing levels and a decent overnight re-freezeÂ will certainly help. Which was the case with my re-visit to the lines above in Coire Ardair today (Below)
Whilst nobody wouldÂ advocate jumping up and down even after a re-freeze theÂ rate of creep is certainly stalled at such times. By the same token the features are not going away and propagation is very muchÂ assistedÂ by Â further thaws – particularly those accompanied by theÂ additional lubricating properties of any rain working its way to underlying sliding surfaces!…….
As an aside many years ago with theÂ 3 times predecessor of the current SIT Â which I was puttingÂ through training courses with SARDA (Search and Rescue Dog Association). I was at an exercise in Glencoe and had spent some time attempting to put the dog out from a ridge line I was ascending to search a coire bowl. Having failed miserably to get the beast to cooperate I was trudging down dejectedly for an early lunch assuming neither of us would be participating further in the afternoon activities.
Not so – 30 mins after arrival back at base the entire section of the bowl duly avalanched!
I never did work out 1. was it a happy coincidence 2. Â did I just get luckyÂ 3. was the dog smarter.
I suspect a combination of all 3!
The worry is current ‘SIT’ smarter than predecessors.
NB. No canines harmed in the making of this blog!
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