Snow Observations List

We dug three snowpits over the course of two days from 11/12 to 11/13 around Cooke City and found a weak layer 20-30cm above the ground at various aspects and similar elevations. The weak layer was composed of small rounding facets and was less than 1cm thick. The weak layer was at the interface between old and new snow. The old snow below the weak layer was composed of coarse, rounded/rounding faceted grains. The new snow above the weak layer ranged from 60-80cm in height and was right-side-up, progressing from fist hardness at the surface to one-finger immediately above the weak layer. Test results were as follows:

Goose Lake – NE aspect, 10,100 ft (45.11627, -109.92057): ECTP25, 80cm deep. HS 110cm

Scotch Bonnet – SW aspect, 9,800 ft (45.07038, -109.94489): ECTN (*did propagate 60cm deep on "31st" tap, a very hard whack after no formal result). HS 80cm

East Henderson – E aspect, 9,700 ft (45.05855, -109.94966): ECTP29, 65cm deep. HS 90cm

Additional notes: 11/12 had clear skies, no wind, and warm temps. A 5 cm thick sun crust formed on SE, S, and SW aspects. No natural nor human-triggered avalanches were observed on 11/12-11/13. A continuous cornice had formed along the entire N-S ridgeline on the east side of Henderson by 11/13. 

Our group of four went to Bridger Bowl to evaluate the snowpack and get some decent turns. We dug a pit at the bottom of the pitch of hidden gully at 7460 ft and found a graupel layer sitting on an ice crust that was a layer of concern. Since the snow above it wasn't cohesive enough to form a slab we found Q3 fracture quality at ECTP 23. As we transitioned to ski after skinning further up towards hidden gully there was a much more reactive wind slab that formed near the surface. We were at 7990 ft on a ENE aspect and found 5 cm of fresh soft storm snow on top of a 13 cm wind slab that was 4F+ in firmness. The CT results were a Q1 fracture on 1 tap and this was alarming. Our group was ready to ski and for this reason an ECT test was not performed, but this alarming CT result made us rethink our original plan of skiing directly along a wind loaded gully where we found the weak wind slab layer to be. The quick pit that showed this wind slab was dug below a rock outcropping between hidden and northwest passage. We believed this was a concern specific to this terrain feature and that that reactive of a wind slab was unlikely to be found away from this outcropping. We felt that in sheltered and treed areas that aren't getting sluff and wind deposited snow dumped on them because of their terrain features we would be safer. 

It was cold and snowing most of the day with 1-2" of low density new snow by 3pm. We dug 3 pits: at the top of Tyler’s, and top and Middle of Spanky’s. Our pits were 40-70 cm deep and we had ECTXs and a couple ECTNs(23-25) around 30cm above the ground on top of older, slightly more faceted snow. For now stability is generally good with primary problems being wind slabs. It seems the snowpack is shallow enough it will only get weaker without much snow in the forecast.

Skied around Mt. Henderson the last 2 days- 

No avalanche activity observed.

3 snow profiles.  ECTP's in 2 of 3 snowpits.

Also, we experienced at least 6 large collapses while touring the last 2 days, often after 10+ people up the same skin track.

When walking around near grotto falls and below fat and thin chance there was significant surface hoar forming. The crystals near fat and thin chance appeared to be 1mm in size and near the grotto falls parking lot specific areas had surface hoar up to 3 or 4mm in size. 

Skied Hyalite Peak today and found a wind slab ~10cm deep. Ski cut a small cornice below the main face and broke a small slide that carried ~20’ with little energy with a ~25’ wide crown

While on a tour today out in Republic Creek, we decided to skin a forested W aspect to gain woody ridge. As we started to near the alpine, we dug a pit on a N aspect at 9900ft and in return got a ectp24 at 30cm in our test. Snowpack in the area was roughly 110cm. The snowpack failed on a buried crust layer that has not bonded to the new snowfall.

~72 cm depth

ECTN13 @ 45cm

ECTP17 @ 30cm 

Location:

East Aspect

45.32868, -111.38167

12T 0470091E 5019534N

9311 ft

Essentially the same results as were shared in the forecast this morning.

ECTX on our snow pit on a shaded, west-facing aspect but sun has created a thin crust as well as some pretty large facets on the surface. Looked like wind had collapsed most of them but could cause problems after next storm

Looks like this could be a problem when buried.

We toured up to the Ramp through Bridger Bowl this morning. This week's winds hammered the snow at mid-elevations (from the bottom of the Alpine/ Powder Park Lifts to the top of Bradley's Meadow). Some areas were scoured to near the ground, with pencil-hard wind drifts in others. The winds hadn't affected the snow from the bottom of the ramp to the ridge as much. We dug a pit on the Ramp halfway up. There was 90cm of snow on the ground in the pit. The bottom 38cm is faceting into sugary grains, but they aren't remarkable yet. ECTN23 at the top of the facet layer at 38cm from the bottom. My primary concerns were thin snow cover and slopes with wind drifts from the past few days. Calm up there today. 

There are many barely covered rocks on the Ramp. There was a lot of skier and boarder traffic all over the mountain. Cars were parked in the F lot when we left. 

Strong temperature inversion in the AM, -4F in the meadow and about 20F at the ridgeline. Sunny by late morning with light winds. The southern aspects were getting baked pretty good in the sun. We were getting roller balls and snow globbing on our skis on the SE aspect to the south of the standard skin track. 

About 60 cm of snow at the top. Soft (F hardness snow) basically to ground. Almost no wind loading. Definitely can see some of the snow at the very bottom starting to facet a bit. We saw A LOT of surface hoar mid slope and down in the meadow, but very little toward the top. The northerly aspects had no obvious signs of instability yet. I'd expect the surface hoar and/or an extended period of dry weather could set up some interesting weak layers over the coming days/weeks depending on how the weather plays out.

Some fresh bear tracks on the skintrack into Sheep Creek a few weekends back. Funny to share a route with the wildlife. They're still out and about, make sure to carry your bear spray for a few more weeks!

I attached a few photos of a small wind slab avalanche (R1 D1)  from yesterday at approximately 7800 feet on the northern end of bradleys meadow. 

The slide was initiated by the second skier and although the rest of the slope was <30 degrees the starting zone was a NE facing steep cross loaded wind pillow just below the ridge. 

As my friend was skiing down he saw a crack propagate up and to his left and was able to stop on the side of the path as the snow ran past him. The  crown was approximately 30-40 feet and ran about 100 feet. 

Here are the coordinates of  a way point I dropped just above the top of the slide : 

45° 50.0218′ N, 110° 55.7420′ W

 we circled back and took a photo of the top as well...  let me know if you need anything else! thanks! 

We were at the ridge of middle basin @9400 feet. Before skiing we dug a pit and weren’t thrilled with the results. CT broke on the barrier between the fresh snow and the first dump that the area had. We got an ECTP 17 that went all the way across at the same old snow- new snow barrier @ 35- 40 cm from the ground. Stuck to the lower angle terrain and had a great day.

Me and my buddy went on a tour today up Sheep Creek to check out the new snowfall and conditions in the area. We dug a pit on a S\SE aspect at 9500 feet and found about 100cm snowpack. Last weeks snowfall fell right side up and was not able to find layers until the bottom 6 inches of the snowpack. About 6 inches from dirt, there is a minor crust layer with small facets under the crust. We did not find the new snow to be reactive to this layer during our column test...

Around 2ft down in the pit that was dug there is a generally stable storm slab but it still broke after 5 elbow strikes. Finger tip strikes did trigger a 3-4 in wind slab in the pit and a remotely triggered wind slab was observed halfway up the whiteworm. 40 wide and 5 in deep it ran for about 60 yd.

A skier remotely triggered an avalanche on Mt Blackmore (11/9/22).

From email: "I ski cut the top of the face and remote triggered a hard slab from 50’ above the crown. It broke full width of the couloir feature, 150’ wide and 10-18” deep. Broke on new snow/old snow interface which was another hard wind slab. The avalanche ran the length of the East face and stopped just below the last set of cliffs."

The pit depth was approx 80cm to the ground. Slope angle 19 Degrees. Air Temp 19* F. E/NE facing slope. Hardness Test/ Fist @ 64 cm, 4F @ 45 cm, 1F @ 35 cm, 4F @ 20 cm. Conducted CT (30cm x 30 cm column), Propagated at 25 (10 wrist, 10 elbow, 5 shoulder) propagation was just below the distinct layer that you can see at 35cm in the photo labeled BM5. Then conducted ECT (90 cm X 30cm) No propagation after 30 ( 10,10,10). Picture labeled BM4 is the layer that propagated on the column test.

Small slab avalanche triggered by skier in a small chute near The John and Bronco runs in Bridger Bowl. Propagation from skier’s ski, slab slid down through the chute. Crown maybe 10 feet wide. Slab looked about 6 or 7 inches thick. Looked like a layer of new snow from today and yesterday’s storm sliding on top of an old crust layer. Nobody harmed, just spooked. Watch out!