Incident

Avalanche: Antelope Island

UAC ObserverSalt Lake
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Avalanche

Slab Width
6 m
Weak Layer
Depth Hoar
Trigger Type
Skier
Vertical Fall
46 m
Avalanche Type
Hard Slab
Slab Thickness
46 cm
Trigger Detail
Unintentionally Triggered
Start Zone Aspect
Northeast
Avalanche Problem
Persistent Weak Layer

I was skiing the second part of our run, the snow transitioned from storm snow to wind slab with a couple inches of low density snow on top. As I was skiing and took 3 or 4 turns on the slab the slope ripped underneath me and the snow continued down the gully. The weak layer was at the ground, old faceted snow, with wind deposited and storm now on top.

The second photo shows the whole slide path. The gully had facets and a wind slab on it while the slopes on either side did not.

This slide was triggered remotely shortly after the first one. The aspect was the about same (almost due north) and the slope was slightly steeper. It too broke on facets near the ground. This slide had much more power and slid about 200 yards. Looking at the second photo, the furthest right track you see before it traverses into the bed surface is where the skier remotely triggered it.

The bed surface was super sugary and there were large chunks of wind slab on the flanks.

This final photo shows a photo I took up in Alexander Basin in Mill Creek during the inversion. Notice that the tip of Antelope Island is exposed while the rest is socked in. This potentially explains why the steep larger slopes we skied at higher elevations were more stable than the lower elevation slopes that slid (on a relative scale of course, it was all "low elevation terrain"). Perhaps facets grew more in the clouded and cooler lower elevations and not at the higher ones that were able to get some sun. I put this out there to emphasis the odd conditions mentioned in yesterday's forecast. With this wacky storm and lots of snow at lower elevations, the conditions are not the same everywhere and people may be motivated to ski places that are uncommon (so think about what your doing). The snowpack on Antelope Island, for instance, was very thin and much different than up in the Wasatch at 10,000'.

Incident

Number Caught
1