21-22

Large natural avalanche on Cedar Mountain

Cedar Mtn.
Northern Madison
Code
N
Latitude
45.22680
Longitude
-111.51200
Notes

The Big Sky Ski Patrol saw this natural avalanche as it occurred. "This morning around 8:45AM myself and my route partner were doing control work in hanging valley. I watched as he prepared a shot and saw a big cloud of snow on Cedar behind him. As I was looking I saw an avalanche appear from below the blowing snow. I watched it run from near the top of the ridge to the runout approximately 800-1000 ft below. It looked like most of the bowl was involved in the avalanche so I estimate the crown to be likely 1000ft wide. It looked to not be an enormous amount of volume so I estimate it to be likely between 6in and 2ft. We did not get a good view of crown as weather moved in shortly after and winds were strong."

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
Vertical Fall
1000ft
Slab Width
1000.00ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural avalanches near Cooke City

Zimmer Creek
Cooke City
Code
SS-N-R2-D1-I
Elevation
9000
Aspect
SE
Latitude
45.09990
Longitude
-109.88400
Notes

Skiers near Zimmer Creek observed a couple natural avalanches that occurred during the day and early this morning on 3/14/22.

Another group reported: "Avalanche on Mt Fox, E aspect that likely ran on the same layer. Visibility was too poor for a photos. D2-R1 ran aprx 400' feet and crossed the bench at its Southern edge for about 100'."

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
12.0 inches
Vertical Fall
100ft
Slab Width
150.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Skier remote triggered, Zimmer Creek and whumphing

Zimmer Creek
Cooke City
Code
SS-ASr-R1-D1-I
Elevation
9000
Aspect
SE
Latitude
45.09990
Longitude
-109.88400
Notes

"skier remote trigger while performing a ski cut, also in Butter. All slides [observed today] were D1, storm slab on mfcr, solar aspects

Also observed a couple large wumpfs and cracking on lower angle slopes. This new snow warmed up significantly today, pretty touchy out there."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
12.0 inches
Vertical Fall
100ft
Slab Width
25.00ft
Weak Layer Grain type
Melt-freeze crust
Slab Layer Grain Type
Precipitation Particles
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural and skier triggered storm slabs

COOKE CITY
Cooke City
Code
SS-N-R3-D2-I
Elevation
9000
Aspect
SE
Latitude
45.02020
Longitude
-109.93800
Notes

Numerous 10-12" SS remote triggered avalanches on anything steep enough to slide where the new snow fell on solar crust. [Natural on] the cliffs on the north side of Companion Lake as you leave the lake heading for the wilderness boundary. Had not avalanched on the way out in the morning, noticed the avalanche on the way back this afternoon. Another avalanche skier triggered on intentional test slope with a solar tilt in the Alp Gulley."

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
3
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
12.0 inches
Vertical Fall
150ft
Slab Width
200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

GNFAC Avalanche Forecast for Tue Mar 15, 2022

Snowpack and Avalanche Discussion

<p>It is possible to trigger dangerous avalanches in the mountains around Cooke City after this weekend’s 13” of snow and associated wind (<a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><strong>weather log</strong></a>). Slopes prone to wind loading or that have obvious drifts are the most likely to avalanche. Riding north of Cooke City yesterday, Alex saw natural and human-triggered avalanches mostly failing a foot deep, taking out the recent snow (<a href="https://www.mtavalanche.com/node/26193"><strong>photos and details</strong></a>, <a href="https://www.youtube.com/watch?v=5aiYFlLV05M&amp;list=PLXu5151nmAvT1nrM2…;). However, layers of weak snow buried around two feet deep make larger avalanches possible as Ian saw north of Scotch Bonnet last week (<a href="https://www.youtube.com/watch?v=BGiz4qC7pQg"><strong>video</strong></a&…;). A dozen observed avalanches since Saturday paint a clear picture about the possibility of triggering slides (<strong><a href="https://www.mtavalanche.com/avalanche-activity">avalanche activity</a></strong>). Avalanches becoming less likely as the snowpack adjusts, but patience or a thorough snowpack assessment is vital.</p>

<p>Look for signs of instability and test the upper few feet of the snowpack looking for information telling you to stay off steep slopes. Safe travel protocols provide a buffer if your assessment is wrong.</p>

<p>Today, the danger is MODERATE in the mountains around Cooke City. Snowfall this afternoon will increase the avalanche danger.</p>

<p>It is possible to trigger avalanches 6-18” deep on a melt-freeze crust or a layer of weak facets in the mountains around Bozeman, Big Sky and West Yellowstone. Strong winds will transport snow onto slopes where avalanches are most likely. Yesterday, skiers triggered multiple avalanches on the east face of Mount Blackmore, one from 50’ away (<a href="https://www.mtavalanche.com/node/26199"><strong>photos and details</strong></a>), and a group of snowmobilers sent in a photo of a slide on a wind-loaded slope below a cornice near Buck Ridge (<a href="https://www.mtavalanche.com/node/26195"><strong>photos and details</strong></a>). Two days ago, a skier took a nasty ride and sustained minor injuries in the backcountry outside of Big Sky Resort on a heavily wind-loaded slope when he triggered a 1000’ wide avalanche that carried him over rocks (<a href="https://www.mtavalanche.com/node/26184"><strong>photos and details</strong></a>). Sunday, in Beehive Basin, my partner and I found weak snow and bailed to a lower angle slope due to unstable test results at the top of a steep slope (<a href="https://www.youtube.com/watch?v=NTjHmlc7JHg"><strong>video</strong></a>…;

<p>Wet snow avalanches are possible, especially at lower elevations where temperatures will be warmer and precipitation may begin a rain.</p>

<p>Give yourself a chance to turn around by assessing the snowpack and looking for signs of instability before skiing or riding in avalanche terrain. The avalanche danger is MODERATE.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</p>

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