Posted on: 2015-04-17 00:49:26 by davidof

Spring slabs

Normally, this time of year, after a good refreeze we can expect wet snow slides on sunny slopes but the avalanche bulletins have talked about "natural slides that take the form of wet slabs with a linear fracture line, fairly large with unusual trajectories". So what's up?

Alain Duclos has posted a description of one of these slabs. He spotted the slab at the Pointe d'Andagne above Bonneval near the "3000" ski lift. This was triggered by a small, wet snow slide taking out a massive wet slab resting on a deeply buried weak layers at the end of the day. The slab comprised a number of different layers. There have been similar observations by the guardian of the Promontoire refuge in the Ecrins and another on the west face of the col d'Emy in the Maurienne. On the 16th April four off piste skiers triggered an avalanche near the Pendine at Puy St Vincent, a small slide resulted a much larger slab. The ski resort had to close the sector as a precaution. On the 13th a female ski tourer suffered s shoulder injury in the chourum Olympique in the Hautes-Alpes at around 13h00 (the third slab triggered on this ski touring route this season). It seems that the weak layers are being reactivated in certain sectors on slopes that, superficially at least, appear stable.