GNFAC Avalanche Forecast for Fri Mar 6, 2020
<p>We still can’t trust the snowpack in the northern Gallatin Range. The weak snow near the ground remains unstable. While it’s now been a week since the last avalanche was triggered on this layer by a snowcat groomer in Swan Creek (<strong><a href="https://www.mtavalanche.com/node/22269">details</a></strong>), stability tests continue to show lingering instability. On Wednesday, Doug returned to the site of the groomer triggered slide and got unstable results on an adjacent slope (<strong><a href="https://youtu.be/25MQg4PXJd4">video</a></strong>). On Tuesday, skiers got similar results in thin areas on Mount Ellis. These thin areas are where the snow remains most unstable. Dig and assess the snowpack before committing to steep slopes. For today, triggering avalanches remains possible and the <u>dry snow</u> avalanche danger is MODERATE.</p>
<p>Across the rest of the advisory area, the snowpack is generally stable. Avalanche activity on deeper weak layers had been very limited with just one slide over the last couple weeks (<a href="https://www.mtavalanche.com/weather/wx-avalanche-log">Weather and Avalanche Log</a>). Still, there are weak layers lurking at the bottom of the snowpack and cornices pose a real hazard. Cornices have gotten huge and with the warm temperatures they are failing. Yesterday, near Cooke City a cornice broke and triggered a small wind slab near Sheep Mountain (<strong><a href="https://www.mtavalanche.com/node/22334">details</a></strong>). Minimize your time exposed below cornices and give yourself a wide margin if you’re traveling on a corniced ridgeline. For today, triggering <u>dry snow</u> avalanches is unlikely and the danger is rated LOW. </p>
<p>If you get out, please send us your observations no matter how brief. You can fill out an <strong><a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a></strong>, email us (<strong><a href="mailto:mtavalanche@gmail.com" target="_blank">mtavalanche@gmail.com</a></strong>), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.
COOKE CITY
Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.
BOZEMAN
Cornice triggered wind slab near Cooke
Small skier triggered wet loose slides in Bridgers
From email: "Steep south facing slopes would readily push small loose wet slides if you were skiing it, all other solar slopes took heat but didn’t seem to heighten the avalanche danger. "
GNFAC Avalanche Forecast for Thu Mar 5, 2020
<p>The northern Gallatin Range is harboring weak snow near the ground that is unstable. This layer consists of large grains of sugary facets called depth hoar. Six days ago a large avalanche was triggered on this layer by a snowcat groomer (<strong><a href="https://www.mtavalanche.com/node/22269">details</a></strong>). Six days is a while go, but stability tests continue to show this weak layer failing. Skiers saw it on thin areas of Mount Ellis two days ago, and yesterday I dug on an adjacent slope to the groomer-lanche with unsatisfactory results. The column broke cleanly in 2 of my 3 tests (<strong><a href="https://youtu.be/25MQg4PXJd4">video</a></strong>). Although the likelihood of triggering slides is decreasing, it is doing so at a slower rate than other mountain ranges. Many slopes are stable, but some are not. The most unstable snow is found on slopes with less than 4 feet of snow, so dig and assess before committing. For today, the <u>dry snow</u> avalanche danger is MODERATE since avalanches are still possible.</p>
<p>Excluding the northern Gallatin Range, evidence of recent instability is lacking in our forecast area. The most current avalanche activity with a buried weak layer was 8 days ago in Hourglass Gully in the Bridger Range (<strong>photo</strong>), and over 2 weeks ago in the other ranges. The <a href="https://www.mtavalanche.com/weather/wx-avalanche-log">Weather and Avalanche Log</a> has all the details. Today, around Cooke City, there may be a few wind-drifts from yesterday’s 2-3” that could break, but these would be small and isolated occurrences. Throughout southwest Montana, cornices are drooping heavily and ready to break free, often times much farther back than we can imagine. We’ve gotten alarming reports of skiers getting dangerously close to the edges. Besides pummeling you in a fall, breaking cornices have killed when they trigger avalanches. Given the widespread weak layer of sugary facets in the bottom of the snowpack, this scenario is not out of the question. For today, without any new snow or wind-loading, <u>dry snow</u> avalanches are unlikely and the danger is rated LOW. </p>
<p>If you get out, please send us your observations no matter how brief. You can fill out an <u><strong><a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a></strong></u>, email us (<u><strong><a href="mailto:mtavalanche@gmail.com" target="_blank">mtavalanche@gmail.com</a></strong></u>), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.
COOKE CITY
Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.
BOZEMAN
Cornice triggered avalanche on Ramshorn Peak
The date of the avalanche is a best guess based on other activity.
From an email, " It did look like the east face of Ramshorn Peak slid pretty recently. The blowing snow and clouds weren't conducive to good pictures but you can see the crown line below and to the right of the summit. Looked like a cornice fall triggered it."
From an email, "It did look like the east face of Ramshorn Peak slid pretty recently. The blowing snow and clouds weren't conducive to good pictures but you can see the crown line below and to the right of the summit. Looked like a cornice fall triggered it." Photo: B. Richards
Forecast link: GNFAC Avalanche Forecast for Fri Mar 6, 2020