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Avalanche: Tony Grove Area

Observer Name
Jeremy
Observation Date
Wednesday, December 16, 2020
Avalanche Date
Wednesday, December 16, 2020
Region
Logan » Logan River » Tony Grove Area
Location Name or Route
South of Tony Grove Lake - “The Lower Slit”
Elevation
8,700'
Aspect
Northeast
Slope Angle
38°
Trigger
Snowboarder
Trigger: additional info
Intentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Wind Drifted Snow
Weak Layer
Facets
Depth
12"
Width
35'
Vertical
150'
Comments
I noticed some heavily wind loaded areas with drifts 12-16" deep bordering the line I was planning to surf so I cut into the drifts with my Powsurfer in hand. We've referred to this area as "the lower clit" for decades. Sure enough shooting cracks. I then chopped my board into the snow and pulled, releasing the initial slide that was roughly 30 feet wide, running 150 feet or so into dense trees below. Debris pile was around 4 feet deep at the couch at the bottom just before the thick trees. Certainly enough to bury a person and definitely enough to mangle someone in the tight woods below. I continued up the ridge approaching another drifted zone and did the same, releasing another slide about 40 feet wide running the same length into the tight woods below. I continued up Ridge from there to the top of my intended line and it was pretty clear that the upper part of that bowl was going to release as well so I slope cut that on my powsurfer to release it as well. so the slide width pictured was actually 3 separate intentionally triggered slides. depth of crown(s) varied from 5-14 inches.
Comments
If local forecasters return to this area I would highly recommend continuing to cut the rest of this snow field to release the rest of it. I had to leave or I would have done it myself. the slab failed on a slightly crusted bunch of sugary faceted snow.
Comments
The color coded photo shows the initial trigger point in red, 2nd trigger point in yellow, 3rd in green. About half of this little hanging bowl slid and the rest to the lookers left will very likely slide with the smallest trigger. Very tight trees below this so a very dangerous spot for even a small slide. Blue points to debris pile and the area where I'm standing was piled 4 feet or so deep.
Video