Northern Gallatin

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.

From Obs: "With a ski cut, I released a very small slab that entrained 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." Photo: W Gober

From Obs: "With a ski cut, I released a very small slab that entrained 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." Photo: W Gober

We dug a snow pit on an E facing slope NTL and found a non-reactive, layered snowpack. We got a score of 22 on our ECT with no propagation on what is presumably a new-old snow interface, where the newer snow was on top of wind effected older snow. We did no other tests. 

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. 

From obs. 2/27/22: "... on our way up Flanders. Near ridge line there’s a 3-4”, dense wind slab that was quite touchy. I chucked a basketball size piece of cornice onto a small test slope and observed it collapse and crack." Photo: S. Gill

Found 2-4 mm SH on our way up Flanders. Near ridge line there’s a 3-4”, dense wind slab that was quite touchy. I chucked a basketball size piece of cornice onto a small test slope and observed it collapse and crack. 

From message 2/27/22: "Skier triggered yesterday in a northeast wind loaded pocket on baldy in S Bridgers. About 6 inches deep and 100ft wide.
Quite a bit of shooting and cracking elsewhere at lower elevations. Felt wind loaded just about everywhere after those east winds." Photo: J. Keogh