21-22

Hellroaring Hut

Date
Activity
Skiing

Skiid the into the Hellroaring Drainage 12/29/21-1/2/22. Did not observe any natural slide activity or indicators of instability during the tour into the hut. Snow depth was consistently 130 cm at 8000'. Skiid W & NW aspects up to 35 degree slope angle. Fair structure + Good Strength = Generally Stable Conditions in the Eastern Centennial.

WNW aspect, 8,000' HS 130 cm
CT3 Q3 @ 20 cm (new snow)
CT20 Q2.5 @60 cm (new snow)
ECT-N+

Region
Island Park
Observer Name
Hellroaring Powder Guides

Large Natural on Mt. Abundance

Mount Abundance
Cooke City
Code
N-R3-D2.5-O
Elevation
10000
Aspect
E
Latitude
45.07730
Longitude
-110.02100
Notes

Riders saw the crown of this slide on 1/2/21, and it appeared to be many days old.

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
3
D size
2.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
48.0 inches
Vertical Fall
1000ft
Slab Width
2000.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Upper Pebble creek

Date
Activity
Skiing

Hi guys, this is an actual obs! Not a test this time.
The s. facing side of Pebble Creek was clearly wind affected, by what seemed to be S and SW winds. In leeward areas, skiing was good; in exposed areas, it was only 20cm deep. Strangely, we didn't really observe and hard wind slabs.

Region
Cooke City
Location (from list)
Pebble Creek - YNP
Observer Name
Jim Earl

Centennial Mountains, Tin Cup Pass

Date
Activity
Snowmobiling

We rode into the Hell Roaring drainage via Willow Creek to Tin Cup Pass from the Keg Springs parking lot in Idaho. There was no recent avalanche activity observed along this route. I dug one pit at Tin Cup Pass on the Montana side at 8000' on a NW aspect. Total snow depth was 165cm and the snowpack was relatively homogenous with the exception of one melt freeze crust near the bottom of the snowpack at 39cm. From the melt freeze crust to the ground the structure was very sugary. A CT and an ECT were completed with results as follows, CT 12 @135cm, CT 28@ 115cm, and ECTN 16@ 150cm. My greatest concern in the snowpack was the melt freeze crust near the bottom of the snowpack.

Region
Island Park
Location (from list)
Centennials - Montana
Observer Name
Chris Hericks

Shale Creek

Date
Activity
Snowboarding

Toured up to 8200 feet to North facing meadow that drops into Shale Creek. Lots of new downfall to navigate on the approach. Shallow snowpack. We dug a pit just below high point on a due North aspect, slope angle was 28 degrees. Height of snow was a paltry 50cm with a simple snow structure from surface to ground: 10cm Fist hard newish snow, 25cm 4finger soft slab, 10cm layer of Fist hard large grained faceted crystals (4mm), on top of a basal ice crust of 5cm on the ground. We performed an Extended Column Test and got propagation on the layer of facets on the crust at 12 loading steps (ECTP 12). Cold temps have weakened the shallow snowpack which is noticeably less dense and supportable than it has been. 

Region
Dillon Area
Location (from list)
West Pioneer Mountains
Observer Name
Kris Thomas

GNFAC Avalanche Forecast for Mon Jan 3, 2022

Snowpack and Avalanche Discussion

<p>A person can trigger avalanches 1-5 feet deep, within or below snow that fell over the past couple weeks. Strong southwest wind will drift snow into fresh slabs that could avalanche under the weight of a person. These drifts could be large enough to bury someone and could trigger an avalanche deeper and wider on buried weak layers (<a href="https://www.youtube.com/watch?v=K4yEaUsqo6A"><strong>Lionhead video</strong></a>). The last three days without new snow mean it is becoming more difficult to trigger large avalanches breaking below the recent snow, but it is still possible. Yesterday riders near Cooke City reported an avalanche on Mt. Abundance which is a few days old, but it shows what is possible and an example of type of terrain to stay away from today (<strong><a href="https://www.mtavalanche.com/images/22/large-natural-mt-abundance-1">pho…;, <strong><a href="https://www.mtavalanche.com/images/22/large-natural-mt-abundance-2">pho…;). Today, human triggered avalanches are possible and the avalanche danger is MODERATE.</p>

<p>In the Bridger Range avalanches are possible to trigger and could break 1-3 feet deep below drifts that formed over the last week. Large natural avalanches on Saddle Peak that occurred late last week are a sign to remain cautious of wind-loaded slopes (<a href="https://www.mtavalanche.com/node/25329"><strong>details</strong></a&gt;, <a href="https://www.mtavalanche.com/images/22/natural-large-wind-slab-argentina…;, <a href="https://www.mtavalanche.com/images/22/natural-avalanche-saddle-peak"><s…;). Within the last week both Dave and I found weak, faceted snow buried up to a foot deep below recent snow (<a href="https://www.youtube.com/watch?v=Iv0tVbc9VZw&amp;list=PLXu5151nmAvT1nrM2… Peak video</strong></a>, <strong><a href="https://www.youtube.com/watch?v=kXE-CWnV_NY">northern Bridger video</a></strong>). This layer has us worried that deeper avalanches are possible to trigger. Additional weight from wind-drifted snow today keeps the avalanche danger heightened, and on their own these fresh drifts could be unstable and potentially harmful. Today avalanches are possible to trigger and avalanche danger is MODERATE.</p>

<p>Strong winds today are drifting snow into shallow slabs. Due to minimal recent snow for wind to drift, in only isolated areas will fresh slabs be unstable and large enough to be harmful. Otherwise, the snowpack is generally stable and large avalanches are unlikely. If you plan to venture into steep terrain today, continuously assess the potential for unstable drifts and consider the consequences of being&nbsp;caught in even a small slide. Yesterday, skiers in Hyalite backed-off steep, consequential terrain after their snowpack assessments revealed potential unstable wind slabs sitting on weak snow. Today, large avalanches are unlikely and avalanche danger is LOW.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

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