19-20

"...today we toured into an east aspect in the N. Madison. Winds were stronger than we anticipated, already western sides of ridges had been scoured to near bare ground. While skinning along the ridge we intentionally triggered large wind drifts and small cornices. We dug a pit on a south/south east aspect and got ectp 25. While skiing a low angle meadow back out to the ridge a member of our party remote triggered a small slide on a wind loaded pocket on an east aspect. According to my partner it was 75 ft wide and maybe a 1-2 feet deep.

Northern Madison, 2020-02-11

Collapsing and Cracking on Mt. Ellis

Mt Ellis
Northern Gallatin
Code
Elevation
8000
Aspect
E
Latitude
45.57770
Longitude
-110.95500
Notes

"I observed this collapse & propagation as I stepped over some wood in the skinner on the north ridge of Mount Ellis this morning, ~8000’, due East. I was tailing Chabot and his partner, and they had passed this way just minutes before."

Number of slides
0
Number caught
0
Number buried
0
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year

"I observed this collapse & propagation as I stepped over some wood in the skinner on the north ridge of Mount Ellis this morning, ~8000’, due East. I was tailing Chabot and his partner, and they had passed this way just minutes before." Photo: D. Rider

Northern Gallatin, 2020-02-11

Natural Avalanches West of Beehive Peak

Beehive Peak
Northern Madison
Code
SS-N-R3-D2-I
Elevation
9200
Aspect
SW
Latitude
45.35390
Longitude
-111.40500
Notes

From an obs.: "Large crown in lower meadows west side of beehive basin above jack creek. Both meadows in lower fight of photo went. Southwest aspect. Far right meadow crown is visible and entire face went. Left meadow is hard to see but 1/3 of face slid. I would guess 3-6 foot crown from how visible it was from moonlight."

Another report: "Observed good size crowns from Beehive Basin Road. They were on the west side of the ridge dividing Beehive Basin and Jack Creek. They were not down to the ground but big and wide looked like probably all the recent snow from the storm."

Number of slides
2
Number caught
0
Number buried
0
Number killed
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
36.0 inches
Slab Width
300.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

I observed some good size crowns from Beehive Basin Road this afternoon. They were on the west side of the ridge dividing Beehive Basin and Jack Creek. They were not down to the ground but big and wide looked like probably all the recent snow from the storm. Photo: T Grande

Northern Madison, 2020-02-11

I observed some good size crowns from Beehive Basin Road this afternoon. They were on the west side of the ridge dividing Beehive Basin and Jack Creek. They were not down to the ground but big and wide looked like probably all the recent snow from the storm. Photo: T Grande

Northern Madison, 2020-02-11

GNFAC Avalanche Forecast for Tue Feb 11, 2020

Snowpack and Avalanche Discussion

<p>Increasing winds today will form fresh drifts out of last week’s 50-60” of snow that will crack and avalanche in steep terrain. While the new avalanche problem to watch for today will be wind-loaded slopes, we aren’t out of the woods from the largest loading event of the year (3-4.5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> in the last seven days). Indeed, it was just 24 hours ago that the mountains around Big Sky and Bozeman reported up to a foot of new snow. Two days ago, Alex searched the Bridger Range for the fallout from the storm and said, “It would be easier to list the steep slopes that didn’t avalanche than those that did.” This included one avalanche in Truman Gulch that broke over a mile wide (<a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank"><strong>photos</strong></a>,&nbsp;<a href="https://www.youtube.com/watch?v=MXPxJvSz-uk&amp;list=PLXu5151nmAvSbcbVf…; target="_blank"><strong>video</strong></a>) and a slide that broke naturally across Saddle Peak failing 4-8’ deep (<strong><a href="https://www.mtavalanche.com/images/20/natural-saddle-peak-deep-slab-cro…;, <strong><a href="https://www.youtube.com/watch?v=tJUrhcTRHac&amp;list=PLXu5151nmAvSbcbVf…;). Photos and reports continue to come in from observers in the Northern Gallatin, Madison, and Bridger Ranges documenting trees snapped of by the force of slides and huge debris piles far down in runout zones (<a href="https://www.mtavalanche.com/photos"><strong>photos page</strong></a>,<a href="https://www.mtavalanche.com/avalanche-activity&quot; target="_blank"> <strong>avalanche log</strong></a>).</p>

<p>Dangerous avalanche conditions continue today as increasing winds load slopes with fresh drifts of snow and the snowpack slowly adjusts to snow from the last week. Cautious route-finding and conservative terrain choices are essential. Human triggered avalanches are likely, and the danger is rated CONSIDERABLE on all slopes.</p>

<p>While not a green light, the snowpack around Cooke City and West Yellowstone is adjusting well to the 2-3’ of snow in the last week and the avalanche danger is coming down. Doug and I spent the last two days riding through the Lionhead and Southern Madison regions and the most remarkable thing we saw was the lack of significant natural and human triggered avalanche activity (<a href="https://www.youtube.com/watch?v=vOKh3V6ZDJ0&amp;list=PLXu5151nmAvSbcbVf… video</strong></a>, <strong><a href="https://www.youtube.com/watch?v=1kW1KxfjQK8&amp;list=PLXu5151nmAvSbcbVf… Fork video</a></strong>). We noted several avalanches within the new snow and when the wind picks up, there is a lot of ammunition to rapidly build drifts of snow that will avalanche. Skiers and riders in Cooke City reported similar conditions observing avalanches that failed during and immediately after the storm breaking 2-3’ deep and sensitive wind drifts breaking 4-6” deep (<a href="https://www.mtavalanche.com/images/20/natural-avalanche-2-3-deep-cooke"…;, <strong><a href="https://www.mtavalanche.com/images/20/cooke-city-storm-slabs">2</a&gt;, <a href="https://www.mtavalanche.com/images/20/human-triggered-small-avalanche-c…;, <a href="https://www.mtavalanche.com/images/20/human-triggered-small-avalanche-c…;).</p>

<p>Human triggered avalanches are possible, and the danger is rated MODERATE. Assess the snowpack for instabilities, be obsessed with the consequences of a slide before committing to avalanche terrain, and avoid slopes recently loaded by the increasing wind.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an&nbsp;<a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank"><strong>observation form</strong></a>, email us (<a href="mailto:mtavalanche@gmail.com&quot; target="_blank"><strong>mtavalanche@gmail.com</strong></a>), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.

COOKE CITY

Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.

BOZEMAN