December 1, 2012, Mt. Baker, Bagley Lakes
12/1/12
WA Cascades West Slopes North (Mt Baker)
1728
1
Our goals for the day were: 1) to get outside safely, and 2) to not be in the rain. We decided to go up to Baker and just chill out doing some mellow touring around Bagley Lakes. Because of all of the storm snow and wind they are getting up there, we werent interested in travelling much farther than Austin Pass.
As forecasted, it was snowing steadily at Heather Meadows with a pretty good wind. The lakes have not completely frozen over yet.
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http://farm9.staticflickr.com/8200/8236330411_9f8b3f6d54_c.jpg" />
We stuck to the east side of the lakes, but saw a few solo travelers (two with canine partners) travelling along the west shores.
In most places around the lakes and up towards the road, ski penetration was around eight inches to a foot. In a few areas we encountered a semi-supportable crust. Though we were most concerned about avoiding the lee north & east-facing slopes, we observed plenty of evidence of wind-loading on west-facing slopes as well.
From the Bagley Lakes basin, we had planned, stability permitting, to travel up towards the road on the less-steep northwest-facing slopes northwest of Austin Pass. Wind loading did not look too extensive here, so we travelled up this way. Partially up the slopes, however, and on an area where the semi-supportable crust was present, we felt some whumphing.
Our first thought was we need to get off this slope. Once off it, however, our second thought was lets dig a pit and see whats going on!
We found a safe area, did a compression test, and did see some fractures. With the first elbow whack (the very technical term I wrote down in the field it was CT11, moderate), the column fractured in two areas. The first fracture was 5-6cm (~2in) from the surface, directly under the semi-supportable crust we had noticed earlier. The second fracture was 20-21cm (~8in) from the surface. Both were planar fractures that did not slide easily (Q2, I think).
Im not sure if this picture is at all useful, but I was surprised it turned out at all. Unfortunately theres nothing to indicate scale, but the fracture line you see 2/3 of the way down the portion of column visible in the picture is the second fracture (20-21cm). The 5-6cm fracture under the crust is harder to see in this picture.
![]()
http://farm9.staticflickr.com/8349/8237397774_4dc02ab377_c.jpg" />
My knowledge of detailed snowpack behavior is pretty limited, but we guessed the second fracture was at the interface between the new storm snow and whatever layer it had fallen on, and probably what had caused the whumphing that we had felt. I tried to get an idea of what the weak layer under the new storm snow where the deeper fracture occurred was like, but it was hard to tell.
Our pit was on a slope with an 18-degree incline, facing 306 degrees (just slightly west of NW) at approximately 4400 ft. elevation.
We had been thinking of lapping down back into the basin, but after the whumphing thought the better of it. We continued up to the road, ascended for a bit, and then just skied down the cat track.
I was a bit skeptical about how the day would go given the wind we found when we got up to the parking lot, but we ended up having a great time being in the snow and geeking out a little bit about snow science.
As forecasted, it was snowing steadily at Heather Meadows with a pretty good wind. The lakes have not completely frozen over yet.
We stuck to the east side of the lakes, but saw a few solo travelers (two with canine partners) travelling along the west shores.
In most places around the lakes and up towards the road, ski penetration was around eight inches to a foot. In a few areas we encountered a semi-supportable crust. Though we were most concerned about avoiding the lee north & east-facing slopes, we observed plenty of evidence of wind-loading on west-facing slopes as well.
From the Bagley Lakes basin, we had planned, stability permitting, to travel up towards the road on the less-steep northwest-facing slopes northwest of Austin Pass. Wind loading did not look too extensive here, so we travelled up this way. Partially up the slopes, however, and on an area where the semi-supportable crust was present, we felt some whumphing.
Our first thought was we need to get off this slope. Once off it, however, our second thought was lets dig a pit and see whats going on!
We found a safe area, did a compression test, and did see some fractures. With the first elbow whack (the very technical term I wrote down in the field it was CT11, moderate), the column fractured in two areas. The first fracture was 5-6cm (~2in) from the surface, directly under the semi-supportable crust we had noticed earlier. The second fracture was 20-21cm (~8in) from the surface. Both were planar fractures that did not slide easily (Q2, I think).
Im not sure if this picture is at all useful, but I was surprised it turned out at all. Unfortunately theres nothing to indicate scale, but the fracture line you see 2/3 of the way down the portion of column visible in the picture is the second fracture (20-21cm). The 5-6cm fracture under the crust is harder to see in this picture.
My knowledge of detailed snowpack behavior is pretty limited, but we guessed the second fracture was at the interface between the new storm snow and whatever layer it had fallen on, and probably what had caused the whumphing that we had felt. I tried to get an idea of what the weak layer under the new storm snow where the deeper fracture occurred was like, but it was hard to tell.
Our pit was on a slope with an 18-degree incline, facing 306 degrees (just slightly west of NW) at approximately 4400 ft. elevation.
We had been thinking of lapping down back into the basin, but after the whumphing thought the better of it. We continued up to the road, ascended for a bit, and then just skied down the cat track.
I was a bit skeptical about how the day would go given the wind we found when we got up to the parking lot, but we ended up having a great time being in the snow and geeking out a little bit about snow science.
Great write up - thanks! Nice to see a detailed thought process report where everything went "right". (Which isn't to say I don't appreciate the retrospective incident or near-miss reports, but this report makes me think maybe those near-miss reports are starting to pay off!).
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