Avalanche: Turnagain

Location: Sunburst avalanche investigation

Route & General Observations

We toured up to take a look at the crown of a very large natural avalanche that had occurred 2 days ago on the north side of Sunburst. The culprit for this avalanche was the same weak layer of facets that was buried back on 3/14, and has been responsible for multiple other massive avalanches over the past two days.


Avalanche Details
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Trigger NaturalRemote Trigger No
Avalanche Type Hard SlabAspect North Northwest
Elevation 2500ftSlope Angle 35deg
Crown Depth 24inWidth 1500ft
Vertical Run 2000ft  
Avalanche Details

The avalanche failed on the weak layer of facets that was buried 3/14. The crown of this avalanche is much shallower than the other recent activity we've seen. This is most likely because the crown was so close to the ridgeline that is chronically scoured by winds from any direction. Debris from the avalanche ran all the way down into Lyon Creek 2000' below the upper part of the crown. This is just one of multiple massive avalanches that we've seen in the past two days (natural and human-triggered), and it is likely this general structure is representative of the problem at hand.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.

We started later in the day, with the intention of being out during the hottest part of the day to see how the snow would react if things got warm. High clouds increased early in the afternoon, which helped keep even the southerly surfaces cool and dry. Air temps were in the upper 20's F at the ridgeline and close to freezing at the highway. Winds were calm.

Snow surface

There was soft, dry snow on all aspects right on the surface. Solar aspects had a breakable crust just below the surface that still skied well. Northerly aspects had dry, settled powder.


We dug a pit right at the crown of a very large avalanche. The setup was clear- there is a hard slab sitting on top of a really weak layer of facets. It was not surprising to find those facets, but it was a little surprising to see how big they were and how soft they were in the pit wall (2 mm crystals, F- hardness). It is an unsettling snowpack and it would not be at all surprising to see more large avalanches like this in the near future. See attached photos and snow profile for more detailed snowpack information.

Photos & Video
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