Observation: Public
Observation Details
Name:
Enji CooperObservation Date:
January 29, 2021Submitted:
January 30, 2021Zone or Region:
West SouthActivity:
Snowmobiling/SnowbikingLocation:
Kahuna Peak/Norse PeakObserved Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Wet LooseSize:
Size 1: Relatively harmless to peopleElevation:
Below treelineAspect:
SComments:
Noted several small (technically D0.5) runs down below tree line when going up the Norse Peak Trail towards near treeline below ridge to Kahuna Peak.Signs of Unstable Snow
Did you see shooting cracks?
NoDid you experience collapsing or whumpfing?
Yes, IsolatedObservations
Day started out mostly sunny, then progressively became obscured with light snow flurries and became mostly foggy/obscured in mid afternoon. Snow that collected on car at 4k' was around 1" deep.
Snowpack down low in the trees was lower than expected.
Dug a pit at near treeline before entering more avalanche terrain at 46.9652, -121.4724 around 10:30. Observed multiple interesting conditions of concern with 82cm base snowpack (we dug down to dirt).
80cm to 63cm: Fist
63cm to 55cm: 4 Finger plus
47cm-30cm: 4 Finger
30cm-base: Finger plus
Isolated column test noted fracture of top weak storm snow layer at 2~3 loading steps; persistent weak layer demonstrated fracture at 23 loading steps. Didn't note any additional fracturing after that point.
Partner offered (was tired really) to sit on isolated column after the fact and it remained stable :D.
Extended column test didn't demonstrate propagation potential.
Due to uncertainty and the fact that we were traveling near treeline/above treeline all day, I picked a route which followed the south ridge of Kahuna Peak to the saddle junction for Goat Lake trail, then pushed up to the Norse Peak ridge.
There was a wide variety of variable wind scouring on fully exposed southwest facing ridges where wind likely flowed freely over the past few days, which matched the professional observations.
Found deep powder (6" snowshoe; 16" booting) along ridge line in last 1/4 mile to Norse Peak from NW approach, likely wind transported snow.
More details/commentary are found on this WTA report: https://www.wta.org/go-hiking/trip-reports/trip_report-2021-01-29-1190467938 .
Media
Advanced Observations
Observed Avalanche Problem #1:
CorniceComments:
Observed a wide array of cornices on the northern aspects of areas like Kahuna Peak, Big Crow Basin, the high point directly above Kahuna Peak near the Goat Lake Trail saddle junction between Kahuna Peak and Norse Peak ridge.Didn't observe any failed cornices, but we intentionally gave them a wide birth.
Observed Avalanche Problem #2:
Storm SlabComments:
Lots of dry loose storm snow was on top of and below 1/23 stout crust, in particular in the front bowl northwest of Norse Peak. Some of the snow had started consolidating in isolated regions into mini slabs with isolated breaks.Penetration with snowshoes with tails going downhill (pressure applied) was around 6" deep.
Penetration with snowshoes with tails walking laterally (less pressure applied) was between 2" and 4" deep.
Observed Avalanche Problem #3:
Wind SlabComments:
Noted wind slab conditions (hollow sounding) along the ridge in the last 100' vertically to Norse Peak.Heard one whooph sound in this section, but it was isolated and there wasn't any settling or glider cracks that I observed.
The southern aspects were largely wind scoured, so I suspect wind loading was mostly present in the north side, e.g., Big Crow Basin.