21-22

Dry Loose Sluff's - Frazier Basin

Date
Activity
Skiing

Frazier Basin has approx. 2-3 inches of very low density snow sitting on an ice hard base. There is no cohesion between these two layers. We skied multiple north facing chutes throughout the afternoon - generally near the ridgeline was very wind affected down to bare rock/wind blasted snow (ice). There was no windloading on the aspects we skied. Where it hadn't been blown off, the low density snow skied well. We started multiple dry loose sluffs, though none were big enough to carry a skier. Natural dry loose sluffs off of steeper features could be seen throughout the basin. With more accumulation I would be very hesitant enter this terrain, due to the very poor interface between the low density snow and the hard base below. When skinning, your downhill ski would constantly slide out on this interface - we resorted to setting a bootpack out of the basin. 

Region
Bridger Range
Location (from list)
Frazier Basin
Observer Name
Cole Herdman

GNFAC Avalanche Forecast for Mon Mar 7, 2022

Snowpack and Avalanche Discussion

<p>Yesterday riders saw a recent snowmobile triggered avalanche that broke 2 feet deep and more than 100 feet wide on Scotch Bonnet Mtn. (<a href="https://www.mtavalanche.com/node/26107"><strong><u>photo and details</u></strong></a>). A couple weak layers of snow which formed in January and early February are buried 1-2 feet deep and make large avalanches possible to trigger. We have seen regular avalanche activity on these layers over the last two weeks (<a href="https://www.youtube.com/watch?v=Ev2Fq5NQGjU&amp;list=PLXu5151nmAvR9KcA-… update video</u></strong></a>, <a href="https://www.mtavalanche.com/avalanche-activity"><strong><u>activity log</u></strong></a>). Most recently, on Thursday natural avalanches broke ~100 feet wide in Republic Creek, Hayden Creek, Sheep Creek (<a href="https://www.mtavalanche.com/images/22/natural-avalanche-republic-creek-…; </strong><a href="https://www.mtavalanche.com/node/26073"><strong><u>details</u></strong>…;) and Pebble Creek (<a href="https://www.mtavalanche.com/images/22/natural-avalanche-pebble-creek-2"…;, <a href="https://www.mtavalanche.com/images/22/natural-avalanche-pebble-creek"><…;), on Friday skiers triggered an avalanche remotely from a low angle ridgeline above the slope (<a href="https://www.mtavalanche.com/images/22/remote-triggered-avalanche-near-c…;), and on Saturday skiers had a large collapse of the snowpack on low angle terrain (<a href="https://www.mtavalanche.com/node/26090"><strong><u>details</u></strong>…;).</p>

<p>Today avalanches can break at least 1-2 feet deep, up to a couple hundred feet wide, and can be triggered from lower angle slopes that are connected to steep slopes. Before you travel on or underneath steep slopes carefully assess the snowpack for unstable buried weak layers, and assess the consequences of being caught in an avalanche. Today avalanches are possible and avalanche danger is MODERATE.</p>

<p>Large avalanches are unlikely near Bozeman, Big Sky and West Yellowstone. Be on the lookout for isolated areas of instability like where hard slabs of wind-drifted snow sit on top of weak snow buried 6-18” deep. During recent field days we saw the weak snow that we’ve been talking about since January will still be a problem when we get more snow (<a href="https://www.youtube.com/watch?v=6Yq1RmjMMJ4&amp;list=PLXu5151nmAvT1nrM2… Ridge video</u></strong></a>, <a href="https://www.youtube.com/watch?v=Nfudo3K5_dM"><strong><u>Lionheaad video</u></strong></a>). The last reported avalanches on these weak layers were last weekend. A lack of snow over the last week allowed the snowpack to become more stable without added stress. Yesterday in Hyalite, skiers had a small wind slab crack under their skis while they descended from a high ridgeline (<a href="https://www.mtavalanche.com/node/26105"><strong><u>photo and details</u></strong></a>). Increased northwest-west wind today will drift a few inches of recent snow into some very small, fresh soft slabs. These could be hazardous if they knock you off your feet in high consequence terrain.</p>

<p>Watch for cracking of the snowpack around your feet or skis as a sign fresh drifts may be unstable. If you plan to ride on steep slopes, carefully assess the snowpack to be sure there is not weak snow buried below a thick slab of snow. Today the avalanche danger is LOW. Expect danger to increase with new snow over the next couple days.</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><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Upcoming Education Opportunities

See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events.

Every Saturday near Cooke City, 10 a.m.-3 p.m. FREE snowpack update and transceiver/rescue training. Stop by for 20 minutes or more at the Round Lake Warming Hut.

Snowmobile triggered large slab on Scotch Bonnet

Scotch Bonnet
Cooke City
Code
HS-AMu-R2-D2-O
Elevation
10000
Aspect
N
Latitude
45.07540
Longitude
-109.95000
Notes

Riders saw the crown and debris of an avalanche on the north side of Scotch Bonnet on 3/6/22. It appeared to have happened that day or within 24 hours.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 inches
Vertical Fall
200ft
Slab Width
150.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Shooting cracks and unstable pit on Alex Lowe

Alex Lowe Peak
Northern Gallatin
Code
Elevation
9500
Aspect
E
Latitude
45.42720
Longitude
-111.01400
Notes

From obs 3/6/22: "Skinned out to Alex Lowe peak today. Dug a pit on a northeast aspect below the east face of the peak. Got an ECTP 24 to break around 20 cm down. The slab was a knife hard sun/wind crust. Continued up avoiding areas where we noticed that bullet hard crust under the surface. On our decent we skied off the east ridge below the summit and on a skit cut got some shooting cracks, and a small wind slap to propagate but not slide. Skied the rest of the way down and didn’t notice anything else."

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

This slide was seen on 3/6/22 and appears to have been triggered by a snowmobiler. It is on the north aspect of Scotch Bonnet Mtn. near Cooke City. Photo: S. Strenge

Cooke City, 2022-03-06

Natural avalanches in Pebble Creek

Pebble Creek - YNP
Cooke City
Code
SS-N-R2-D2-O
Elevation
8900
Aspect
E
Latitude
45.02540
Longitude
-110.03100
Notes

Avalanches in Pebble Creek near Cooke City. Likely occurred on March 3rd, due to the very warm temps. Easterly aspects, around 8900'.  Approx 1' deep and 50-100' wide. 

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
12.0 inches
Slab Width
100.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Avalanches in Pebble Creek near Cooke City. Likely occurred on March 3rd, due to the very warm temps. Easterly aspects, around 8900'.  Approx 1' deep and 50-100' wide. Photo: B. Fredlund

Cooke City, 2022-03-06