20-21

Beehive

Date
Activity
Skiing

Skied the east side of Beehive Basin today. Light snow and intermittent, moderate winds throughout the day once you gained some elevation. About 30 cm of very low density snow on top of weak sugary snow at the base.

On SW facing slopes found a sun crust about 10cm from the ground, about 4F hardness.

Snow is about 60 cm deep and generally F hardness all the way to the ground. It's still easy to find the bottom but coverage is improving.

I did not observe any significant wind loading, yet. I suspect that will change in the coming days as there was plenty of wind to transport plenty of new snow load. I'd be concerned about any wind slab forming on top of the base we have out there.

Region
Northern Madison
Location (from list)
Beehive Basin
Observer Name
Chris Pierce

Getting worse at Lionhead and Centennials

Date
Activity
Snowmobiling

Both the Lionhead area and the nearby Centennial Range in Idaho have a similar snowpack. About 20-25" are on the ground consisting of weak, faceted, sugary snow. Riding is supportable, but we tiptoed around Lionhead because of rocks.Snow and wind are forecasted in the oming week. This snowpack will become unstable quickly. I expect to see cracking, whumpfs and recent avalanche activity. Small avalanhes on road cuts or creek banks are bulls-eye data that big avalanches are likely. Be careful, pay attention and stay clear of creeks and other terrain traps where even a small slide can be deadly. We made a video that outlines our concern which is posted on the Centennials page.

Region
Island Park
Location (from list)
Ski Hill
Observer Name
Doug Chabot

GNFAC Avalanche Forecast for Tue Dec 15, 2020

Snowpack and Avalanche Discussion

<p>Snow tapered off yesterday in the mountains around Bozeman, Big Sky, and West Yellowstone with snow totals ranging from 5 to 8” equal to 0.3-0.4” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) since Friday. Yesterday, moderate west winds in the Bridger Range created small drifts near ridgelines (<a href="https://www.mtavalanche.com/images/20/cracking-drifted-snow"><strong>ph…;). Light winds in the rest of our area did not move much snow. These ranges have a weak foundation that will avalanche when loaded with a slab of new or wind drifted snow, but we are not there yet (<a href="https://www.youtube.com/watch?v=cUnquoQ5kXU"><strong>Beehive video</strong></a>, <a href="https://youtu.be/aqBSydiYMYk"><strong>Hyalite video</strong></a>, <a href="https://www.youtube.com/watch?v=NDfD3-tTguk"><strong>Saddle Peak video</strong></a>, <a href="https://www.youtube.com/watch?v=4quJW8upKQg"><strong>Buck Ridge video</strong></a>, <a href="https://www.youtube.com/watch?v=pKWi6VcTnzI"><strong>Lionhead video</strong></a>).</p>

<p>Instabilities today will be limited to loose snow avalanches in steep, rocky terrain like those I observed in Hyalite (<a href="https://mtavalanche.com/images/20/loose-snow-avalanche-divide-cirque"><…;) and Beehive (<a href="https://mtavalanche.com/images/20/small-loose-snow-avalanches-beehive">…;) in the last two days and isolated drifts of snow. These small avalanches could have outsized consequences if they push a skier or rider into obstacles such as trees or off cliffs. They are occasionally entraining the weak, faceted snow near the ground and gaining volume (<a href="https://www.mtavalanche.com/images/20/full-depth-facet-sluff-s-madison"…;).</p>

<p>Be obsessed about the consequences of small avalanches and carefully assess the snowpack looking for isolated instabilities before entering avalanche terrain. Today, avalanches are unlikely and the danger is LOW.</p>

<p>The snowpack around Cooke City is stronger and deeper than the rest of our advisory area and it is supporting the 4” of new snow (0.3” SWE) from this weekend. While the snowpack is generally strong, skiers and riders have found slopes with weak layers of surface hoar and sugary facets (<a href="https://www.youtube.com/watch?v=Xj-qhUPJigw"><strong>video</strong></a&…;, <a href="https://www.mtavalanche.com/images/20/surface-hoar-near-goose-creek"><s…;). Dig down to assess the snowpack to look for these instabilities. Learn how and what to look for in Doug and Bruce Jamieson’s recent ECT <a href="https://www.youtube.com/watch?v=Gk8W8nlUMpw&amp;list=PLXu5151nmAvQDzKmH…;. Instability today is limited to isolated drifts of snow and small, loose snow avalanches in steep, technical terrain that can knock a rider or skier off their sled or feet.</p>

<p>Carefully assess the snowpack and consequences of a small slide before entering avalanche terrain. Today the avalanche danger is LOW.</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>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Upcoming Avalanche Education and Events

See our education calendar for an up to date list of all local classes. Here are a few select upcoming events and opportunities to check out:

History Rock

Date
Activity
Skiing

Toured History Rock today and skied the upper and middle meadows. Saw around 6 inches of storm snow sitting on top of faceted grains. The upper meadow snowpack varied from 30-50 cm with the deeper snow being closer to the bottom. It was all unconsolidated snow and did not observe any instabilities. Pretty good skiing!

Region
Northern Gallatin
Observer Name
Nick Roe

We observed a cluster of relatively small, loose snow avalanches in the Tyler's Slide area of Beehive Basin. We don't have the recipe for slab avalanches... yet. Wind-loading and/ or new snow could tip the scales. Both are coming this week and next, so stay heads-up! Photo: GNFAC

Avalanche Details: Natural Loose Snow Avalanches - Beehive Basin
Forecast link: GNFAC Avalanche Forecast for Tue Dec 15, 2020GNFAC Avalanche Forecast for Wed Dec 16, 2020GNFAC Avalanche Forecast for Fri Dec 18, 2020
Northern Madison, 2020-12-14
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