20-21

Ramp

Date

Digging holes and rescuing backpacks on top of Bradley’s today. Caught a few glimpses of old crowns, all ran mid-storm. Several size 1-2 storm slabs on the interface in Revolving Door and on the apron below. Looked like a storm slab stepped down to something deeper on the lookers R side of the apron in Wolverine, crown partially filled but looked 1m+, solid size 2 as far as I could tell through the trees.

Any new snow is falling on top of low density stellars, the upper 5-10cm were touchy on this interface, several fresh shallow crowns, cracking etc.

ECTX on top of Bradley’s in 3/3 pits. This area has been strangely stable in tests all year despite seemingly poor structure.

Observer Name
Sam H

Divide cirque

Date
Activity
Skiing

Toured in divide cirque today. There was about 24” of fresh snow which made trail breaking very difficult. I did a quick pit and found a fist hard slab sandwiched between two layers of very low density snow. My guess is this layer formed when the cold front passed last night. I stuck to low angle terrain. In the basin, between pt 10,201 and 10,024 there was a very large avalanche that must have slid yesterday or last night. It looks like it propagated at least 1000’ wide and at the deepest the crown was easily 5 feet. Visibility was low so it was hard to tell, but it was definitely a big slide. Light snow in the AM became moderate in the afternoon, and it began accumulating rapidly.

Region
Northern Gallatin
Location (from list)
Divide Cirque
Observer Name
Nicholas Salsburg

Blackmore

Date
Activity
Skiing

Skied off the shoulder of Blackmore today. No recent avalanche activity was evident, not even sloughs down the face. New snow was right side up and well bonded. Was still seeing propagation in pits in the low to mid 20s range though. Generally breaking on a layer of faceted snow sitting below a melt freeze crust about 2ft down.

Region
Northern Gallatin

GNFAC Avalanche Forecast for Sat Feb 6, 2021

Snowpack and Avalanche Discussion

<p>Another foot of new snow fell yesterday in the Bridger Range onto a remarkably weak snowpack. 30” of snow (3” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</u></a>) have accumulated since Wednesday. This is a huge load and makes for very dangerous avalanche conditions. This new snow is falling onto the weakest snowpack we’ve had in years (<a href="https://www.youtube.com/watch?v=OYjGdWjKAzc&amp;list=PLXu5151nmAvQDzKmH… showing that weak snow in December</u></strong></a>). Strong gusty west winds have compounded the problem. With wind gusts into the 50s mph last night expect wind-loading in unusual places. A dusting of fresh snow on top will make it hard to identify loading patterns. Keep it simple: <strong>avoid all steep slopes to avoid triggering a big slide</strong>. With especially weak snow near the ground, stay well out from under steep slopes as well because you could trigger a slide from below. A large natural avalanche broke to the ground yesterday on a low elevation slope just above Fairy Lake (<a href="https://www.mtavalanche.com/node/24082"><u>details</u></a&gt;). Human triggered avalanches are likely today. The avalanche danger is HIGH on wind-loaded slopes in the Bridger Range and CONSIDERABLE on all other slopes.</p>

<p>New snow, very strong winds, and a weak snowpack are a bad recipe. Human triggered avalanches are likely across the Madison and Gallatin Ranges. Skiers yesterday in the southern Gallatin and Madison Ranges had the snowpack whumpf and collapse under them. If they were on steep slopes they would have triggered avalanches. Last weekend, big slides broke deep and wide on weak layers mid-pack and near the ground (<a href="https://youtu.be/CI0HFvtLrf4"><strong><u>Lionhead video</u></strong></a>, <a href="https://youtu.be/dVWv0RA9WMM"><strong><u>Ernie Miller video</u></strong></a>). With more new snow, similar slides are likely today. The avalanche danger is CONSIDERABLE in the Gallatin and Madison Ranges.</p>

<p>Yesterday, a skier triggered and was partially buried by an avalanche that broke 1-2 ft deep on a weak layer just below the new snow on Woody Ridge (<a href="https://www.mtavalanche.com/node/24075"><strong><u>details</u></strong>…;). Alex was north of town yesterday and also concerned about weak layers lower in the snowpack waking up with more loading (<a href="https://www.youtube.com/watch?v=u1BY8bb327k&amp;list=PLXu5151nmAvQDzKmH…;). Snowfall is going to ramp up in intensity today. Human triggered avalanches are likely and they may break 2-4 ft deep or even deeper on a windloaded slope. Start off with conservative plans and if it’s snowing heavily, tone down your objectives even further. The avalanche danger is CONSIDERABLE.</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>

King and Queen Fundraiser

TODAY and TOMORROW - February 6th and 7th -- AWESOME PRIZES for individuals who raise over $500! Two pairs of skis, Airbag Avy pack, and more! Deadline for fundraising is 1:15 p.m. Sunday, Feb. 7. No racing is necessary to compete for the fundraising prizes. Info is HERE.

Whumpfs at Bacon Rind

Bacon Rind
Southern Madison
Code
Latitude
44.96090
Longitude
-111.10000
Notes

Skiers at Bacon Rind had the snowpack whumpf several times while skinning.

Number of slides
0
Number caught
0
Number buried
0
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year
20-21

Natural avalanche near Fairy Lake

Fairy Lake
Bridger Range
Code
SS-N-R2-D2
Latitude
45.90430
Longitude
-110.95800
Notes

Natural avalanche observed near Fairy Lake on 2/6/21. 150ft wide and varying from 2.5-5ft deep. Broke in the new snow but also stepped down to near the ground.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Problem Type
New Snow
Slab Thickness
30.0 inches
Slab Width
150.00ft
Images
Natural avalanche near Fairy Lake
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21
Subscribe to 20-21