Storm Creek Old Large Avalanche

Avalanche date/time

Sunday, December 27, 2020 at 08:02

Estimated occurrence time of avalanche

More than 48 hours ago

Number of avalanches in this report

1

The size of avalanche

3

Slab width

400m

Run length

150m

Avalanche Character

• Deep persistent slab

Trigger type

Natural

Start zone aspect

• NE

Start zone elevation band

• Alpine

Start zone elevation

2,200m

Start zone incline

35°

Weak layer crystal type

• Facets

Wind exposure

Cross-loaded slope

Sometime during the pre-Christmas storm IT looks like the slope below Storm Creek Headwall from below Kaveology to Smith & Wesson went naturally.

I estimate it was about 400m wide. It ran about 150-200m to the bottom of the valley and a short way into the trees in places. Crown was filling in so can’t say how deep but based on the crusade crossloaded and spindrifted nature of the slope and depth of the snowpack I would guess it probably varied from 1-2m.

I presume it failed on facets deep in the snowpack in order to have such a wide propagation. Presumably the early Nov crust could be implicated though I didn’t find much evidence of that crust on earlier forays to this location.

Likely triggered by avalanche falling from above the headwall.

Of note is that the large couloir right of the headwall also ran 3/4 path but did not pull a slab down low.