GNFAC Avalanche Forecast for Sat Jan 11, 2020
<p>6 to 12” of low density new snow fell near Big Sky overnight. Moderate to strong southwest winds have built thick drifts on windloaded slopes. Snowfall totals have been variable across zone over the last three days – the greatest danger is in areas with the most new snow. If you find deep new snow and thick wind drifts, avoid all avalanche terrain. Avalanches can break under the new snow, or much deeper, including all the way to the ground (<strong><a href="https://www.mtavalanche.com/images/20/avalanche-ground-yc">photo</a></s…;, <strong><a href="https://www.youtube.com/watch?v=7vDe6LE-nhU&list=PLXu5151nmAvSbcbVf…;). Human triggered avalanches are likely and the avalanche danger is CONSIDERABLE.</p>
<p>Triggering an avalanche is likely in Cooke City on any steep slope today. While the deep powder from this week’s storm is settling, weak layers deeper in the snowpack will take longer to heal from the large load they’ve received since New Year’s (40” of snow with 4” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… snow water equivalent</a>). Yesterday, riders near Daisy Pass saw a fresh snowmobile triggered avalanche on Chimney Rock and a larger natural avalanche that broke during the storm (<strong><a href="https://www.mtavalanche.com/images/20/snowmobile-triggered-slide-chimne…;, <strong><a href="https://www.mtavalanche.com/images/20/natural-avalanche-miller-mountain…;). Give these weak layers more time to adjust - stay off steep slopes today. Dangerous avalanche conditions exist and the avalanche danger is CONSIDERABLE.</p>
<p>With little new snow overnight, the wind drifted slabs that formed in the Bridger and Northern Gallatin Ranges over the previous several days will be harder to trigger today. However, caution is still merited. Yesterday, Dave got a dramatic test result near the Throne and decided to stick to lower angled terrain (<strong><a href="https://www.youtube.com/watch?v=WUM0Q69fPZE&list=PLXu5151nmAvSbcbVf…;). Stay on alert for signs that wind drifts have remained unstable – cracks shooting out from your ski tips are a clear sign to find a lower angled or less windloaded slope. The avalanche danger is MODERATE today.</p>
<p>The mountains around West Yellowstone haven’t been seen much new snow this week. The snowpack is slowly adjusting and becoming less unstable (<strong><a href="https://www.youtube.com/watch?v=omt8Tt1rwms&list=PLXu5151nmAvSbcbVf…;). However, there is widespread weak snow at the ground that remains worrisome. On Thursday, I remotely triggered a small slide (6” deep and 10’ wide) from 100’ away on a low elevation slope near Hebgen Lake(<strong><a href="https://www.mtavalanche.com/images/20/hebgan-lake-road-cut-avalanche-ja…;). Triggering larger slides remains possible. For today, the avalanche danger is rated MODERATE.</p>
<p>If you get out, please send us your observations no matter how brief. You can fill out an <strong><a href="https://www.mtavalanche.com/node/add/snow_observation">observation form</a></strong>, email us (<strong><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></strong>), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>
Webpage dedicated to the Centennial Range in Idaho and Montana
After the two snowmobiler avalanche fatalities on Reas Peak in the Centennial Range in January 2018 we created a webpage so riders could get good, relevant information regarding snowpack and avalanches.
YC Patrol triggered avalanche to ground
Yellowstone Club Ski Patrol triggered a slide with explosives, breaking at the ground, during avalanche mitigation work on Friday, 1/10/2020.
From Yellowstone Club Patrol: "It’s a NE facing slope at 8500’ ... got an avalanche to release on an old layer of well defined surface hoar (perhaps from mid-December). In some areas it stepped to ground. The crown was 2-4’ deep and the avalanche was recorded as R3/D2. The avalanche slid to the bottom of the runout and placed 3-12’ of snow in the road and completely blocked the road. This was a relatively large slide for this particular path this early in the season."
Yellowstone Club Ski Patrol triggered a slide with explosives breaking at the ground during avalanche mitigation work on Friday, 1/10/2020.
Forecast link: GNFAC Avalanche Forecast for Sat Jan 11, 2020GNFAC Avalanche Forecast for Sun Jan 12, 2020
Snowmobile Triggered Slide on Chimney Rock
Snowmobile triggered avalanche on the WSW face of Chimney Rock near Daisy Pass. Likely triggered morning of 1/10/2020.
Natural Avalanche on Miller Ridge
Natural avalanche on a steep east facing windloaded slope of Miller Ridge. Photo taken 1/10/2020. Likely broke Tuesday or Wednesday during the storm.
Natural avalanche on a steep east facing windloaded slope of Miller Ridge. Photo taken 1/10/2020. Photo: B. Zavora.
Forecast link: GNFAC Avalanche Forecast for Sat Jan 11, 2020
Snowmobile triggered avalanche on the WSW face of Chimney Rock near Daisy Pass. Appeared fresh on 1/10/2020. Photo: B. Zavora.
Windslab in Middle Basin
Small windslab on the apron of the Buttcrack Chute in Middle Basin. Likely broke 1/9 or morning of 1/10/2020.