Large persistent slab avalanches

La qualité du hors-piste était:

Excellente

Les conditions de neige étaient :

• Croûtée
• Poudreuse

Nous avons parcouru:

• Pentes alpines
• Pentes de faible inclinaison
• Pentes ensoleillées

Nous sommes restés à l'écart de:

• Pentes convexes
• Pentes raides

La journée était:

• Ensoleillée

Conditions d'avalanche

• Whoumfs ou bruits sourds ou fissures qui se propagent.

Large natural persistent slab avalanches in the Rainy hollow area on NW-aspects at 1500m with spectacular propagation ~750m. And a deep slab lower on a moraine feature at 1100m. Observed cornice fall and other slab avalanches on Northerly aspects.

Dug a pit at 1600m on a NW-aspect and found a reactive slab down 45cm that propagated on extended column test ECTP21. It failed on faceted snow below a crust layer. Overall poor structure below this interface with punchy layers and strong over weak layering.

At the surface on the northerly was a layer of surface hoar over a firm supportable surface. Big cornices and evidence of recent cornice failure.