24-25 | Gallatin National Forest Avalanche Center

stable storm snow

Date

Sat, 02/15/2025 - 13:30

Activity

Skiing

Howdy gents! Some pals and I skied the the Throne today. 4-8" of low-med density snow, mostly unaffected by wind. South wind was blowing on and off at 5-15mph throughout the day across the ESE face, and swirling N wind down in the runout below Naya Nuki. Not much for wind transport and we felt good skiing the steep N facing trees and the open snowfield on the NE face. No cohesion noted and storm snow seemed to be bonding well to the underlying varied surface. We did avoid the NE Couloir off the throne as the top appeared to be slabbing up with an isolated S windload. No obvious signs of instability otherwise and fantastic skiing. That said, if the wind starts to ramp up, all bets are off the table in my mind. Washboards on the road in were f@ckin' brutal, but the parking lot was easy/ semi plowed.

cheers, Turnage

(406) 580-3636

Region

Bridger Range

Location (from list)

The Throne

Observer Name

Graham Turnage

Unnamed Wall – Hyalite

Date

Thu, 02/13/2025 - 11:00

Activity

Ice Climbing

Climbing at the Unnamed Wall in the vicinity of The Fat One, there are some 3"–8" wind slabs formed. At least three small pockets had released from 2" to 5" deep. Lots of spindrift and heavy winds filled in parts of our trail in a few minutes.

Region

Northern Gallatin

Observer Name

Eric Landmann

GNFAC Avalanche Forecast for Sat Feb 15, 2025

Snowpack and Avalanche Discussion

With new snow overnight, Wind slab avalanches are the primary concern today. Be on alert in places where you find a lot of new snow. Remote weather stations indicate that the deepest snow (in localized areas around Big Sky) is low density (~5%) and I don’t expect it to form cohesive slabs and avalanche by itself - but even a little wind effect could tip the scales and make it reactive and quite dangerous. Without wind, in the deeper areas, watch for Dry Loose avalanches (sluffs) that could be fairly sizable in steep terrain.

Riders triggered thin Wind Slabs up Storm Castle Creek yesterday (<a href="https://www.mtavalanche.com/node/34169"><…;) and there were quite a few small Wind Slabs triggered on Thursday (<a href="https://www.mtavalanche.com/node/34160"><…. Bridger’s observation,</a> <a href="https://www.mtavalanche.com/node/34144"><… fork of Hyalite observation</a>, <a href="https://www.mtavalanche.com/node/34137"><…. Blackmore observation</a>). New snow could mask signs of these older drifts as well as pile up a load on top of them and keep them reactive.

Watch for areas of wind drifted snow and signs that the drifts are unstable (chiefly recent avalanches or cracking). Assess how well wind slabs have bonded to the old snow before getting onto steep slopes.

The avalanche danger is MODERATE today.

Snowfall totals are not very impressive around West Yellowstone, Island Park and Cooke City and there hasn’t been a ton of wind. As with further north, freshly formed Wind Slabs are the primary concern, but they will be less widespread and not as thick. Look out both for thin fresh drifts and somewhat thicker older drifts that formed during the high winds mid-week.

Persistent Slab avalanches are the wild card in these areas. There hasn’t been a ton of activity on the weak layer that formed towards the end of January, but there has been some (<a href="https://www.mtavalanche.com/node/34156"><… photo</a>, <a href="https://www.mtavalanche.com/images/25/cornice-triggered-avalanche-miner… City photo</a>, <a href="https://www.youtube.com/watch?v=wZ3k35z5Ej8&embeds_referring_euri=h… Fork video</a>). These slides are most likely to be triggered on windloaded slopes, where slabs are more cohesive and thicker. If you do trigger one of these slides it’ll break deeper, wider and be more dangerous.

The avalanche danger is MODERATE.

Read more about GNFAC Avalanche Forecast for Sat Feb 15, 2025

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Weather and Avalanche Log for Sat Feb 15, 2025

Read more about Weather and Avalanche Log for Sat Feb 15, 2025

Read more about Specimen Creek Profile - 14 February 2025

Southern Gallatin, 2025-02-14

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Thin and Weak Snowpack

Date

Fri, 02/14/2025 - 14:00

Activity

Skiing

We toured into Specimen Creek today and rode on E-SE and W aspects. Though more snow exists in this location than is typical, the snowpack here is still shallow and weak.

Our snow profile on a W aspect at 8100' showed us some of the weakest snow structure we had seen this season. Sugary, large-grained facets and depth hoar spilled out of the pit wall at the ground. In this location, a 6" slab sits atop this weak snow, but was not cohesive enough to get unstable test results (HS: 90, ECTX).

Outside of very weak structure, no other signs of instability like cracking, collapsing or recent avalanches were spotted.

While the state of the snowpack now provides better coverage and riding than usual, expect to see a jump in avalanche danger on these shallow, weak slopes when/if they receive another good round of snowfall.

Region

Southern Gallatin

Location (from list)

Specimen Creek

Observer Name

Haylee Darby

Wind Slab Avalanches, Storm Castle Creek

Storm Castle

Northern Gallatin

2/12/2025

Code

SS-R1-D1

Latitude

45.42340

Longitude

-111.12500

Notes

Sledded up storm castle. Spent the majority of the day skinning and skiing NE to NW aspects. Found debris from multiple R1-D1 wind slabs from earlier this week. Found widespread but inconsistent wind slabs (2"- 6" thick) at elevations 6700' to 8400'. Throughout the day cracking and collapsing was noticed multiple times on areas of stiffer snow. Snow quality changed dramatically from powder turns to thick wind crust with no visual surface difference.

Number caught

Number buried

Avalanche Type

Soft slab avalanche

R size

D size

Problem Type

Wind-Drifted Snow