Avalanche: Turnagain

Location: Seattle Ridge backside - several human triggered large avalanches

Date:
Observer:
Route & General Observations

There were several large human triggered avalanches today with debris running into valley bottoms. As of this writing, all have been remotely triggered and from what we know, no one has been caught. Below are a few photos. We will be compiling additional photos and information tomorrow. The snowpack set up is very scary right now. Very large avalanches will remain possible for us to trigger in the days to come. Remember that even if a lot of tracks are on the slope it doesn’t mean it’s safe and it doesn’t mean the next slope or bowl over is safe either.

Thank you to everyone who came out to the Avy Awareness Day at Turnagain Pass today!

 

Avalanche Details
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Trigger UnknownRemote Trigger Unknown
Avalanche Type UnknownAspect Unknown
ElevationunknownSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

All the avalanches triggered today appear to have failed on the old early March 'dry spell' surfaces (facets on shady aspect or sun crust/facet mixes on solar aspects). So the slabs in these slides are composed of all the storm snow starting on March 15th. This is anywhere from 4-7' of snow that has seen varying degrees of wind loading.

Seattle Ridge, 3rd Bowl: Three large slabs released remotely by two snowmachiners in the valley bottom. They likely triggered a collapse in the weak layer that propagated across the entire bowl, including an adjacent slope below them.

Seattle Ridge, Minus 3 Bowl: A snowmachiner triggered a small slab in a depression low on the slope that triggered a collapse that propagated up slope and triggered two slabs then another very large slab around the corner and out of view. These larger slab sent debris over gentle terrain and into Seattle Ck itself.

Skookum Valley: A very large avalanche occurred in the lower section of the Skookum Valley. A preliminary report has already been posted on the observation page.

Photos & Video
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