Quick report
- Slope Angle
- 30°
Avalanche
- Slab Width
- 30 m
- Weak Layer
- Facets
- Trigger Type
- Snowboarder
- Vertical Fall
- 152 m
- Avalanche Type
- Hard Slab
- Slab Thickness
- 46 cm
- Trigger Detail
- Unintentionally Triggered
- Start Zone Aspect
- East
- Avalanche Problem
- Wind Slab
- Start Zone Elevation
- 2774 m
We made it out into Southeast Idaho to check the snow and avalanche conditions. We went out with very low expectations but ended up finding decent riding at high elevations.
We had made several runs in a good location for Considerable avy danger days. We were staying away from a steeper roll-over that has been known to infrequently avalanche. I made a turn at the top of a 30 degree slope that was connected to the slightly steeper slope; a hard wind slab pulled out about 100 feet wide and propegated onto a slope that measured only 28 degrees. The 28 degree slope was where we had just been riding and took out our last four tracks. The deepest part of the avalanche was 3 feet deep and averaged 18 inches across the 100 foot crown. The steepest angle along the crown was 33 degrees and the mellowest angle was 28 degrees. This avalanche was on an east facing slope just over 9000 feet and ran a total of 500 vertical feet.
We took a minute to poke around the crown. The failure occurred just below the rime crust from last week in a faceted layer of snow. This area had received a significant amount of wind over the last few days and the 18-36” slab was pencil hard. We did an Extended Column Test on the slope just above the crown and did not get any failure or definite propagation. We wondered if the recent fracture affected the results...
After the avalanche, we continued to ride the <28 degree slope for several hours with no other cracking or obvious signs of instabilities.