TJ Bowl obs

AVALANCHE OBSERVATION
tj bowl

Drainage:

Submission Info
Thursday, March 8, 2018 - 5:15pm
Avalanche Type: 
Slab
Slope: 
4 045degrees
Trigger type: 
Snowboarder
Crown Height: 
2 ft
Aspect: 
Northeast
Weak Layer: 
Old Snow
Avalanche Width: 
40ft.
Terrain: 
Near Treeline
Elevation: 
9 800ft.
Bed Surface: 
Old Snow
Avalanche Length: 
60ft.
Number of similar avalanches: 
5
More detailed information about the avalanche: 

Toured to TJ Bowl on thursday to see how alpine snow was holding up to windy weather, found a lot of breakable wind skins. Upon aproach watched two riders put a skin track through the bowl and onto the lookers right NE ridge. The NE ridge/moraine connecting TJ bowl to Crystal Crag was littered with D1 and 2 naturals on nearly every convexity that had either run during or near the end of the previous weekends storm. The riders descended one area that had not avalanched through more convex terrain with no immediate result. Yesterday I toured back to the same area, upon arrival at TJ lake I noticed this small R1 D1 pocket that realeased sometime after they had ridden, between yesterday morning and thursday. One riders track skirted the flank of the avalanche and exposed a rock (potential shallow, trigger point). I was unable to inspect crown but looked from afar to have run on new old snow interface, potentially a firm crust possibly caped by facets. The crown was approximately 40ft and 2 feet tall, it ran about 60 feet into trees. 

On Thursday I spent some time on the bed surface of the large R3D3 Tj Bowl slide from the storm cycle. Its crown averaged 4-5 feet and the bed surface was, 1-2mm fist hard facets sitting on top of a pencil hard crust. Bed surface provided consistently predicable, smooth, turns. Other alpine snow was largely wind affected and breakable. 

On Sunday I went back to the large TJ Bowl bed surface, the crown had completely blown in, in places an was still 5 feet tall in others. I could not get any of the newly deposited 4F hard windslabs sitting on the bed surface to propegate with repeated stomping, they took considerable force to shear Q1 in hand pits but no official tests were preformed. I wonder how these northerly facet/crust combo bed surfaces that are currently persistent slab worry free ski slopes will react to new load later this week if the storm materializes.

Avalanche Photos: 

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