Mécanismes de déclenchement des plaques

What we can see, playing “stability games”

L'after-eight du 22 janvier 2021 sur le déclenchement des avalanches :

Pour les plus pressés : La présentation d'Alain et François sur le déclenchement des avalanches

Les 4 étapes du déclenchement

4 étapes du déclenchement

Quelques vidéos

Buried weak layer

Video Basic identification by probing with your ski pole, confirmed (or not) by the compression test.

Crack initiation

Video Compression test (having isolated a column of the snow pack the shovel blade is placed over the column and tapped with the hand).
Video

Weak layer collapse

Weak layer behavior before and after the compression test.

Crack propagation

Video Video Crack initiation using a snow saw to cut the weak layer located below a long isolated slab block, then...

The breaking-off of the slab and its transportation

The « slab » must break off before it slides sliding, if the block has not been pre-cut.

« Bridging index »

Video Multiply the total thickness (cm) of snow layers above the weak layer by their average hardness (1 to 5). If you get less than the critical (empirical) threshold of 130, you may initiate a crack.