Slab problem over fresh snow

Avalanche date/time

Thursday, February 11, 2021 at 12:30

Estimated occurrence time of avalanche

Less than 12 hours ago

Number of avalanches in this report

11 to 50

The size of avalanche

3

Slab thickness

15cm

Slab width

100m

Run length

200m

Avalanche Character

• Cornice with slab
• Loose dry
• Persistent slab
• Wind slab

Trigger type

Natural

Trigger subtype

Accidental

Start zone aspect

• E
• N
• S
• W

Start zone elevation band

• Alpine
• Treeline

Start zone elevation

2,300m

Start zone incline

40°

Runout zone elevation

1,900m

Weak layer burial date

Wednesday, February 10, 2021

Weak layer crystal type

• Storm snow

Wind exposure

Windward slope

Vegetation cover

Sparse trees or gladed slope

Seen many natural overnight avalanches. Triggered avalanches are extewmely likely as there is a slab problem worsening overtop of powdery snow. We seen shooting cracks, slab releases, cornices forming and recent natural avalanches. (And older avalanches from the snow loading from sunday last weekend)

10-20+cm of windswept slab on top

60cm of unstable powder below

70cm down, a sleet layer which failed on a column test

We rode there wednesday the 10th, and overnight wind caused natural avalanches to occur in the areas we had already rode. Breaking near trees on convex slopes, cornice & slab avalanches. One massive avalanche from 2300 meters - 1900 meters occurred, leaving a large pile of snow at the bottom.

We stayed away from wind blown areas, kept clear of avalanche paths, and also kept clear of terrain traps. We also triggered some small avalanches that we did not expect to slide. Take extreme caution. The wind will continue building slab avalanches again overnight tonight as it is windy currently.