Observation: Public
Observation Details
Name:
Enji CooperObservation Date:
January 27, 2022Submitted:
January 27, 2022Zone or Region:
Stevens PassActivity:
XC Skiing/SnowshoeingLocation:
Jim Hill MountainTriggered Avalanches
Did you trigger any avalanches?
YesWas it intentional?
NoAvalanche Type:
Hard SlabSize:
Size 1: Relatively harmless to peopleElevation:
6000Aspect:
NComments:
Was triggering a lot of hard slab breaks with the upper layer back in the Henry Creek drainage basin using snowshoes. All of themObserved Avalanches
Did you observe any avalanches?
YesAvalanche Type:
Wet LooseSize:
Size 3: Could bury and destroy a car, damage a truck, destroy a wood frame house, or break a few treesElevation:
4500Aspect:
EComments:
Signs of Unstable Snow
Did you see shooting cracks?
Yes, IsolatedDid you experience collapsing or whumpfing?
NoObservations
Snow below treeline and near treeline in the morning was very firm—almost resembling Cascade concrete. Was able to boot the entire way up to 4.2k’ with minimal difficulties. Put snowshoes on for additional grip purposes mostly, but they came in handy dealing with fetch in upper basin.
Encountered wind slabs/hard slab in upper basin as described previously. The slabs were extremely touchy and easy to make fail. I got surface layer fractures using my snowshoes and trekking poles on slopes approaching 30 degrees. No other issues were seen with snowshoes.
A quick pit at 6.2k’ on a north facing aspect showed that the snow was mostly right side up, minus a weak layer sandwiched between two stronger layers (4F+ vs Fist). The weak layer was approximately 5cm high, was 85 cm from base, and was buried approximately 15cm down. The failure was difficult to trigger (5 CTH), the slopes has been recently traveled by skiers and boarders, and we hadn’t triggered the particular failure snowshoeing, so I gave my assessment and my partner and I agreed to continue on, mitigating risk by not traveling below one another, communicating, and conducting additional quick tests along the way.
We attempted to summit, but runout was poor and snow conditions weren’t amenable to climbing with crampons, ice tools, and ice axes—low/variable coverage and hard crust over unconsolidated powder without support.
Successfully wore crampons down to 4000’. Postholing was variable, but mostly minimal (2” deep), except when I postholed down 1’ in upper layers.
Snow below 4k’ had refrozen on the walk out. Taking off crampons was a mistake, as some of the snow was sheer ice.
Other notable observation was an old D2-D2.5 wet loose avalanche that seemed to have slid somewhat recently on a eastern facing aspect above 4.3k’ the slide had gone several hundred feet.
Weather was bluebird day until late afternoon, when a weather inversion moved in below 4k’ and remained in the area for the remainder of the evening. S-2 drizzle/snow was falling on the walk out.
Temperatures were in the low to mid 20s near the car at 8:00 and 19:00. Temperatures were somewhat warmer above the basin (6.2k’); anecdotally it felt like it was near freezing in the sun.
Media
Advanced Observations
Observed Avalanche Problem #1:
Wind SlabComments:
Saw a fair bit of wind slab effects up in the upper basin: wind texturing, sounded like styrofoam in areas, satrugi, etc.The wind slab issue propagated a little bit with my snowshoes, but was mostly localized. The slabs were approximately 1”-2” deep and broke in a planar manner.