20-21

"Ran into this slide today. Tail end of Middle Basin. Seemed to have happened sometime in the last week (2/23-24). Most likely during the heavy windloading event. Seemed to run on very small facets we believe formed during the cold spell before the last big storm hit." Photo: S. Knowles
Northern Madison, 2021-03-04

GNFAC Avalanche Forecast for Thu Mar 4, 2021

Snowpack and Avalanche Discussion

<p><u>WET AVALANCHES</u>: Yesterday’s above freezing temperatures made a few wet loose snow slides and pinwheels of snow rolling downhill on sunny, low-elevation slopes. At higher elevations the snow surface either stayed dry or only moistened slightly. Today will be warmer and pinwheels, roller balls and sinking into wet snow past your ankles are signs the snow is wet enough to slide. Seek shady, cooler aspects and stay away from steep slopes that are absorbing heat from the sun.&nbsp;</p>

<p>A skier saw a recently triggered large avalanche on a NW aspect of Big Horn Peak in Specimen Creek yesterday (<a href="https://www.mtavalanche.com/images/21/large-avalanche-big-horn-peak"><s…;). Further to the southwest, Dave and Ian rode around Lionhead and did not see recent avalanches, but did find sugary snow at the ground, some of the weakest they’ve seen. The snow structure is poor (weak snow underlying a dense slab) and triggering an avalanche is still a possibility, although a decreasing one. A few miles north of them in Red Canyon a snowbiker triggered a slide on this layer on Sunday. And on Buck Ridge skiers triggered two avalanches simultaneously that same day (<a href="https://mtavalanche.com/node/24484"><strong><u>details, photos</u></strong></a>, and our <a href="https://youtu.be/8JxETara_7o"><strong><u>investigation video</u></strong></a>).&nbsp; An <a href="https://www.instagram.com/p/CL4xIk5n8PZ/"><strong><u>Instagram post of the avalanche</u></strong></a> and another with <a href="https://www.instagram.com/p/CL-O-73AT5N/"><strong><u>drone footage and a thoughtful analysis</u></strong></a> offer good lessons on decision-making, terrain choice and stability assessment.&nbsp;</p>

<p>No matter the result, a stability test is never a thumbs-up to go into avalanche terrain. It should only be used to stop us. This may seem counterintuitive, but it’s true. Tests inform us when things are unstable and not the other way around. This is especially relevant this season as weak, sugary facets at the ground (depth hoar) are notorious for avalanching when we do not expect it, hence the title of our latest video, “<a href="https://youtu.be/sEjcbv4AWYQ"><strong><u>Low Probability, High Consequences</u></strong></a>”.&nbsp;</p>

<p>With the snowpack becoming wet, plus a weak layer at the ground and recent avalanches, the danger is rated MODERATE on all slopes.</p>

<p>Yesterday, the mountains around Cooke City stayed cool and wet avalanches were not a hazard. It will be slightly warmer today and a few wet loose slides may release on sunny slopes. As a whole, the snowpack is mostly stable because it lacks widespread weak layers. A person could get unlucky on a slope with thin snow cover where pockets of weak facets could avalanche, or you may find a rogue wind drift to release. Even though we are not expecting avalanches, carry rescue gear and only expose one person at a time on a slope, because sometimes the unexpected happens and being prepared is the difference between a good story and tragedy. In general, it’s unlikely to trigger a slide today and the avalanche danger is rated LOW.&nbsp;</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>

The Beacon Park at Beall Park in Bozeman is running!

The Friends of the Avalanche Center in partnership with the City of Bozeman put in a Beacon Park at Beall Park. It is located on the north side of the Beall building between N. Bozeman Ave. and the ice rink. Stop by with your

Large avalanche on Big Horn Peak

Big Horn Peak
Southern Gallatin
Code
U-N-R2-D3
Aspect
NW
Latitude
45.06680
Longitude
-111.05000
Notes

"On the drive back (from Speciman Ck) we saw a large crown on the NW face of Big Horn Peak." It was first noted the afternoon of Sunday, 2/28 and either broke that day or the day before.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Unknown
Trigger
Natural trigger
R size
2
D size
3
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Specimen Creek/Big Horn

Date
Activity
Skiing

GNFAC,
Was up Specimen Creek today, it was HOT. Seemed like everything other than north faces got wet. We found some cold NE and NW facing snow in the AM but it was sticky by the afternoon, plenty of roller balls on steep faces. On the drive back we saw a large crown on the NW face of Big Horn peak, I’ve attached a photo that I took right as we saw you guys drive by in the GNFAC rig haha. I don’t think it was there in the morning, but I could be mistaken.
Spencer

Region
Southern Gallatin
Observer Name
Spencer Jonas

Natural slides in Hyalite Basin

Hyalite - main fork
Northern Gallatin
Code
Latitude
45.38990
Longitude
-110.97700
Notes

These avalanches likely broke around 2/24/21 with other avalanche activity. One was above Hyalite Lake the others were, "Observed two dry-loose slides and one slab avalanche on the NE-facing slope of Peak 10,024 in the Shower Creek basin on Sunday (2/28/21) - all were presumably naturally triggered."

Number caught
0
Number buried
0
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year