21-22

Natural in Argentina Bowl

Argentina Bowl
Bridger Range
Code
SS-N-R1-D2-I
Elevation
8700
Aspect
NE
Latitude
45.78690
Longitude
-110.93500
Notes

From email: "Saw several recent avalanches on the east side of Saddle Peak on my drive up to Bridger this morning. All looked like naturals, I'd guess most were size R1D1 and one R1D2."

GNFAC forecasters saw the same slides which looked to involve the new snow. Most were R1-D1 dry loose and cornice falls, and there was one R1-D2 in Argentina Bowl that was likely a storm slab.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Vertical Fall
900ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural avalanches on Saddle Peak, Argentina Bowl and Pinnacles

Saddle Peak
Bridger Range
Code
L-N-R1-D1-S
Elevation
8600
Aspect
E
Latitude
45.79430
Longitude
-110.93600
Notes

From email: "Saw several recent avalanches on the east side of Saddle Peak on my drive up to Bridger this morning. All looked like naturals, I'd guess most were size R1D1 and one R1D2."

GNFAC forecasters saw the same slides which looked to involve the new snow. Most were R1-D1 dry loose and cornice falls, and there was one R1-D2 in Argentina Bowl that was likely a storm slab.

Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Natural trigger
R size
1
D size
1
Bed Surface
S - Avalanche released within new snow
Problem Type
New Snow
Vertical Fall
600ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

GNFAC Avalanche Forecast for Thu Feb 17, 2022

Snowpack and Avalanche Discussion

<p>The Bridger Range and mountains around Big Sky have the most new snow and the strongest wind. Bridger Bowl’s storm total is 19” equal to 1.5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… water equivalent</u></a> (SWE) and Big Sky’s total is 12” equaling .6” SWE. Some slopes got more than this, others a bit less, but the avalanche story is the same: fresh snow and strong west wind gusting&nbsp;40-50&nbsp;mph will drift snow that can avalanche. Wind-loaded slopes near the ridgelines or in gullies are the most dangerous. This snow fell onto a weak snowpack and in areas where it is piled up deep from the wind a person can trigger avalanches large enough to kill. Our field videos in <a href="https://youtu.be/UkgkgoPLLCQ"><strong><u>Beehive Basin</u></strong></a> and in the <a href="https://www.youtube.com/watch?v=lZoIDq1ZTHk"><strong><u>Bridger Range</u></strong></a> right before the storm show this concern. Yesterday, folks in an avalanche class in Beehive dug 20+ pits and only got 2 unstable test results and they saw no slides. Today’s wind will change that. Shooting cracks in wind drifts on low-angled terrain is a sign that steeper terrain will avalanche. For today, on slopes that are wind-loaded the avalanche danger is rated CONSIDERABLE. On slopes with fresh powder that is untouched by the wind the danger is rated MODERATE. This is not “turn your brain off, look at me,” powder riding because triggering slides remains possible.</p>

<p>Storm totals in Hyalite, the southern Madison Range, Lionhead area and Cooke City were 5-7” measuring .5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314…;. Wind-loading will make some slopes susceptible to triggering because all these ranges have 1 thing in common: the upper 1-2 feet of the snowpack is weak with layers of sugary facets and feathery surface hoar. These layers became unstable in Cooke City last week which is a preview of what can happen elsewhere from this recent storm (<a href="https://www.mtavalanche.com/avalanche-activity"><strong><u>Avalanche Activity list</u></strong></a>). The new snow is not enough of a load to create widespread instability, but it is enough to make avalanches possible on a few slopes that have been wind-loaded or are a bit weaker. Signs of instability like cracking of drifts or natural avalanches will be unlikely, so traveling in avalanche terrain will require homework. In some areas slopes were scoured to dirt, in others wind drifts are hard as concrete, and yet in others the weak layers are preserved. You have to dig down to know what’s under you. In Taylor Fork/Lightning Creek on Sunday I did a cursory stability test before skiing a steep slope, and was glad I did because it revealed instability I was not expecting (<a href="https://www.youtube.com/watch?v=5MFatr0c108"><strong><u>video</u></stro…;). For today, since avalanches remain possible, the danger is rated MODERATE on all slopes.</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.

February 19, Women’s only Companion Rescue Clinic sponsored in partnership with SheJumps! Register Here.