18-19

A skier noticed multiple collapses at History Rock, and snapped a photo of active wind loading at higher elevations in Hyalite. From the email: " Roughly 30cm new snow from the last storm, light winds, although Blackmore (pictured) and Flanders appeared to be getting hammered by the wind. Did a few laps in the top meadow and was getting frequent collapsing on the way back up. One felt like a small earthquake and was the loudest wumpf I've ever heard." Photo: M. Lavery  

Northern Gallatin, 2019-01-24

New snow instabilities in Hyalite

Mt Blackmore
Northern Gallatin
Code
L-N-R1-D1-I
Latitude
45.44710
Longitude
-110.99800
Notes

A skier in Hyalite reported many signs of new snow instability near Mt. Blackmore. From the email: "Widespread shooting cracks and wumphing. Lots of dry loose activity in steep terrain. I saw what I believe was a crown line near the ridge on the north face of Blackmore but it was hard to see because it was in the shade. The wind was gusty and not very consistent, so those wind affected slopes didn’t appear to have set up into harder slabs yet, but I wasn’t about to walk out there to find out!" Photo: H. Coppolillo

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

A skier in Hyalite reported many signs of new snow instability near Mt. Blackmore. From the email: "Widespread shooting cracks and wumphing. Lots of dry loose activity in steep terrain. I saw what I believe was a crown line near the ridge on the north face of Blackmore but it was hard to see because it was in the shade. The wind was gusty and not very consistent, so those wind affected slopes didn’t appear to have set up into harder slabs yet, but I wasn’t about to walk out there to find out!" Photo: H. Coppolillo

Northern Gallatin, 2019-01-24

Big Avalanches on west side of Bridgers

Truman Gulch
Bridger Range
Code
SS-N-R4-D3-I
Elevation
8000
Aspect
NW
Aspect Range
NW, W, SW
Latitude
45.80590
Longitude
-110.93600
Notes

From the ridge late this morning (1/24) we saw multiple large crowns in Truman Gulch on the west side behind Bridger Bowl. Biggest was behind d-route (photo).

Two other slides visible today during brief break before more snow. One behind ridge north R2-D2, and one behind the patrol tow R3-D2.5. All 2-3.5’ deep, latter two not as wide. All big. Broke naturally, probably overnight after 1.6" of swe yesterday and moderate westerly winds. Photo: GNFAC

Multiple Avalanches
Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
4
D size
3
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
34.0 inches
Vertical Fall
1650ft
Slab Width
1200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Avalanche on west side of Bridgers behind d-route at Bridger Bowl. Ran full width of path and over the ice climb well into the flats across summer trail. R4-D3. Crown extends out of left side of photo (marked by red arrows). Avalanche ran down the paths in the foreground as well (marked by black arrows). From the ridge late this morning (1/24) we saw multiple large crowns on the west side behind Bridger Bowl. Broke naturally, probably overnight after 1.6" of swe yesterday and moderate westerly winds. Photo: GNFAC

Bridger Range, 2019-01-24

GNFAC Avalanche Forecast for Thu Jan 24, 2019

Snowpack and Avalanche Discussion

<p>Storm totals are 15-18+” at Bridger Bowl and Big Sky ski areas, 11” in Hyalite, 12” around West Yellowstone and 9” outside Cooke City. The Bavaria weather station at Big Sky recorded 10” <em>last night</em>, so totals may be higher in the northern Madison Range. The snow water equivalent (<u><a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2…;) measures .8” in Cooke City to 1.6” in the Bridger Range.</p>

<p>Leading up to yesterday’s storm were <strong><a href="https://www.mtavalanche.com/avalanche-activity">20 records of instability</a></strong> (avalanches, cracking, collapsing). Yesterday, collapsing and cracking up Hyalite (<strong><a href="https://www.mtavalanche.com/images/19/cracking-and-collapsing-lick-cree…;) and in the southern Gallatin Range were whispers of today’s danger. An inch or more of SWE in 24 hours has ramped up the likelihood of triggering slides. Our snowpack is weak with facets where it is shallow. Skiers proved this when they triggered an avalanche from 100+ feet away on Wheeler Mountain (Monday), a head-snapping warning since <em>all our ranges</em> have many slopes with this same snow structure (<u><strong><a href="https://www.mtavalanche.com/node/19777">details</a></strong></u&gt;, <strong><a href="https://www.mtavalanche.com/images/19/wheeler-mountain-avalanche">photo…;).</p>

<p>Videos from the field outline our concerns. Eric found weak snow in <strong><a href="https://www.youtube.com/watch?v=ABNKUnYcWIQ&amp;t=0s&amp;list=PLXu5151n… Basin</a></strong>, I had slopes crack in <strong><a href="https://www.youtube.com/watch?v=orGDvzUtVcw&amp;t=0s&amp;list=PLXu5151n… City</a></strong> and Alex and Ian found weak interfaces in the <strong><a href="https://www.youtube.com/watch?v=A7iKQ_QWJkY&amp;t=0s&amp;list=PLXu5151n… Range</a></strong>. There were avalanches before the storm, so it’s a safe bet there will be avalanches after the storm. The day after a storm is when I’m the most anxious about someone triggering an avalanche. The snow needs time to adjust to its new load, yet people are impatient. I tend to be conservative in my actions, especially with a weak layer of facets at the ground, yet I know that many are trying to be the least conservative as possible; to ride the edge of being safe and getting good powder without getting caught in an avalanche. Never forget, it’s a sharp and unforgiving edge.</p>

<p>Triggering slides is likely today, especially near ridgelines or above treeline where wind-loading added even more weight to the snowpack. Dig and assess what is under your feet before getting close to avalanche terrain. Avalanches can be triggered from afar so be watchful of not being under steep slopes. For today, given the recent avalanche activity, new snow and wind, the danger throughout our advisory area is rated CONSIDERABLE.</p>

<p>If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u&gt;, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u&gt;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

King and Queen of the Ridge

Saturday, February 2 at Bridger Bowl. This is the Friends of the Avalanche Center’s second biggest fundraiser of the year. Come on out and help us raise some money by hiking and skiing some laps on the ridge. Prizes, camaraderie and a good time is guaranteed.