Observation: Public
Observation Details
Observation Date:
January 16, 2021Submitted:
January 17, 2021Zone or Region:
East NorthActivity:
Snowmobiling/SnowbikingLocation:
Sawtooth Mountains - East of ChelanObserved Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Soft SlabSize:
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few treesElevation:
7300'Aspect:
EComments:
East aspect near treeline. 33deg slope. 7300'. Started (probably during last ppt event a few days prior) as a likely shallow (20cm), small (7m wide) wind slab, ran a short distance, and stepped down (>80cm) and propagated widely (>50m) across the slope. Picked up some wet loose character as it moved downslope. Slide ran >1000' to valley bottom.Signs of Unstable Snow
Did you see shooting cracks?
Yes, IsolatedDid you experience collapsing or whumpfing?
Yes, IsolatedObservations
Nearby pit (same slope) revealed HS 205cm with multiple weak layers terminating with 55cm of faceted depth hoar above ground. No early December crust observed. CT3 @ 10cm (SP Q2), CT6 @ 20cm, CT16 @ 70cm. These three layers failed on similar SH (looking) crystals (2-4mm). Several other large crowns observed on N to E aspects in area. Recent wind deposited snow was reactive but not deep. Snowpack (and likely danger level) at this location appears significantly different from what is being reported for/elsewhere in the North East Zone.