21-22

Wind Loading in Sheep Creek

Date
Activity
Skiing

Short tour out to Ghost Trees today to start our trip. Very strong winds and cornice growth down low in the basin on N aspects. No shooting cracks, just funky wind skin distributed sporadically in the meadow/trees. Solar aspects had a stout melt freeze crust. 

Good skiing in non wind-affected snow. Recycled powder!

Region
Cooke City
Location (from list)
Sheep Creek
Observer Name
Nick Roe

North Gallatin Observation

Date
Activity
Snowboarding

Our group skied into the basin to the north of The Mummy in Hyalite on Saturday. Through the cliffs and bottom gully of the basin we noted stable cold snow with natural sluff coming from cliff faces and trees above us seeing warm sun for the first time in the week. At the bottom of the couloir we got an ECTX with total snow depth of 210cm. With a couple extra hard whacks with two fists after the test I did manage to get it to propagate @114cm. We performed a two different PST's in the upper snowpack at density changes and got PST 78/100 (End) @145cm and PST 67/100 (Arr) @ 166cm.

As we climbed the couloir a wind slab developed which eventually caused us to turn back at just over 9,000'. The wind slab was present on pretty much all aspects and edges of the couloir. Let me know if you have any other questions.

Region
Northern Gallatin
Observer Name
Scott Enloe

Thin Wind Slab Blackmore

Mt Blackmore
Northern Gallatin
Code
SS-ASc-R1-D1
Aspect
SE
Latitude
45.44440
Longitude
-111.00400
Notes

From obs: "We also found a thin to medium wind crust (1-5cm) on east and northerly slopes ATL. Our descent took us down the SE face and off the opposite shoulder from our snow pit down a north-facing chute. There was an obvious wind effect on the snow surface and we found the same wind crust/slab. Upon a ski cut, I released a very small slab that entrain a decent about of snow by the time it stopped ~600 vert. feet lower. It was the thin wind slab sliding on softer snow underneath. There was an already reported, similar avalanche from the same day higher on the face of Blackmore that ran a bit further and bigger. It seems like it had pretty much the same characteristics."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
1
D size
1
Problem Type
Wind-Drifted Snow
Slab Thickness
3.0 inches
Vertical Fall
600ft
Slab Width
20.00ft
Images
Thin Wind Slab Blackmore 2
Thin Wind Slab Blackmore
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
21-22
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