Large persistent slab avalanches

Riding quality was:

Good

Snow conditions were:

• Crusty
• Powder

We rode:

• Alpine slopes
• Mellow slopes
• Sunny slopes

We stayed away from:

• Convex slopes
• Steep slopes

The day was:

• Sunny

Avalanche conditions

• Whumpfing or drum-like sounds or shooting cracks.

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.