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 ‘crevasse’
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 may have noticed the recent addition in our reports of the above icon – and also the somewhat ‘opt out clause’ concerning predictability!
As such the university educated amongst you may question the wisdom of poking such features with a 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-freeze will certainly help. Which was the case with my re-visit to the lines above in Coire Ardair today (Below)
Whilst nobody would advocate jumping up and down even after a re-freeze the rate of creep is certainly stalled at such times. By the same token the features are not going away and propagation is very much assisted by further thaws – particularly those accompanied by the additional lubricating properties of any rain working its way to underlying sliding surfaces!…….
As an aside many years ago with the 3 times predecessor of the current SIT which I was putting 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. did I just get lucky 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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