24-25
GNFAC Avalanche Forecast for Fri Dec 27, 2024
<p><span><span><span><strong><span><span>Human triggered avalanches are LIKELY today. </span></span></strong></span></span></span><span><span><span><span><span><span>The weight of the new snow is overloading widespread weak layers buried 1-2 ft deep (</span></span></span></span></span></span><a href="https://youtu.be/4xSA_C9cPuc?feature=shared"><span><span><span><span><s… Park video</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=FKh0OZ-BnUs"><span><span><span><span><s… Rind video</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=yuTTHqltBiw"><span><span><span><span><s… video</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>). Wind loaded slopes will have the deepest slabs of new snow and will be especially touchy, but slopes without wind effect could slide too. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Yesterday, we got reports of cracks shooting out up to 100 feet in the southern Madison Range with only 2” of new snow (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32643"><span><span><span><strong><span…;). This is a clear indication that weak layers have been pushed right to their tipping point. I don’t expect widespread natural avalanching today - but if you get onto or even near a steep slope, expect to trigger a </span></span></span></span></span></span><span><span><span><strong><span><span>Persistent Slab avalanche</span></span></strong></span></span></span><span><span><span><span><span><span>.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Stick to slopes less than 30 degrees in steepness that aren’t below or connected to steeper slopes. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>As the areas around Island Park and West Yellowstone continue to be favored for snowfall over the coming days, we expect the danger to rise in these areas this weekend.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>For today, the avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Without as much new snow, triggering a slide isn’t quite as likely in the northern Gallatin Range. The same snowpack setup exists as elsewhere and large, dangerous </span></span></span></span></span></span><span><span><span><strong><span><span>Persistent Slab avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>are possible, but the weak layers haven’t been loaded as heavily. Watch out for windloaded slopes where the new snow has been drifted into deeper slabs. Look for shooting cracks, collapses, or unstable test results as signs to avoid steep slopes. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE.</span></span></span></span></span></span></p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Weather and Avalanche Log for Fri Dec 27, 2024
AVALANCHE WATCH for Island Park, Lionhead, S Madison, & S Gallatin
Cracking and Collapsing in Tele Meadows
Widespread cracking and collapsing at Tele Meadows today, primarily in wind-affected areas. Shooting cracks up to 100 feet.
Cracking and Collapsing Yellowstone
Widespread cracking and collapsing at Tele Meadows today, primarily in wind-affected areas. Shooting cracks up to 100 feet.
S1 all day, only about 5cm new by 3pm. Winds mod in the AM, light in the PM from the south.
Still pretty thin cover, lots of sagebrush sticking through on the usual ski runs.
Weather and Avalanche Log for Thu Dec 26, 2024
AVALANCHE WATCH for Island Park, Lionhead, S Madison, & S Gallatin
GNFAC Avalanche Forecast for Thu Dec 26, 2024
<p><span><span><span><strong><span><span>Avalanche danger will be rising</span></span></strong></span></span></span><span><span><span><span><span><span> quickly in the mountains near Island Park that are in the bull’s eye for snowfall today through Monday. I was there </span></span></span></span></span></span><a href="https://youtu.be/4xSA_C9cPuc?feature=shared"><span><span><span><span><s… over a week ago</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, and we found a widespread weak layer of facets buried about a foot+ deep. Strong southerly winds and heavy snowfall today will make </span></span></span></span></span></span><span><span><span><strong><span><span>persistent slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> 2 feet deep likey today. Slopes with wind drifted snow will be even more dangerous and avalanches could break even deeper. For these reasons the avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Now will be a great time to enjoy the snow, but </span></span></span></span></span></span><span><span><span><strong><span><span>take a step back</span></span></strong></span></span></span><span><span><span><span><span><span> today through next week. I would plan on riding in the trees on slopes less than 30 degrees in steepness that aren’t steep enough to slide. As snow accumulates, avoid being underneath all avalanche terrain and any steep slope.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In the mountains near West Yellowstone, Big Sky, Cooke City, and south of Bozeman, wind-loaded slopes from </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32638"><span><span><span><span><span><… winds on Tuesday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> and today will be the main concern. With a widespread layer of weak facets already buried 1-2 feet deep, the additional stress of a wind slab on top will make persistent slab avalanches likely on these slopes. Non-wind-loaded slopes have much less weight from new snow on them (aka stress), but with such a widespread weak layer, avalanches on these slopes remain possible.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Today the avalanche danger is CONSIDERABLE on wind-loaded slopes. The danger is MODERATE on all others. Regardless of the danger, consider stepping back and dialing down your terrain choices as we enter a period with more snow coming and rising danger. Avalanche conditions will be getting worse before they get better. Fortunately, new snow will make great powder for skiing and riding, and slopes less than 30 degrees in steepness will be the safest option.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The Bridger Range has simply received less snow than other areas and should receive less the next few days (although sometime around Sunday night looks promising). These mountains have a </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32609"><span><span><span><span><span><… weak layer</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> as in most of the forecast area that is capable of producing avalanches especially in higher and more exposed terrain with more wind drifting</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Persistent slab avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>are the main concern mostly on wind-loaded slopes. Human-triggered avalanches are possible and the avalanche danger is MODERATE.</span></span></span></span></span></span></p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
GNFAC Avalanche Forecast for Wed Dec 25, 2024
<p><span><span><span><span><span><span>Watch out for </span></span></span></span></span></span><span><span><span><strong><span><span>fresh wind slabs</span></span></strong></span></span></span><span><span><span><span><span><span> that formed as yesterday’s strong southerly winds whipped around the several inches of snow (up to 5” near Cooke) that had fallen over the last four days. </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32638"><span><span><span><span><span><… person in Hyalite Canyon</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> south of Bozeman reported strong winds moving snow all day long yesterday, and Big Sky Resort had to close the summit because of strong winds.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>HEADS UP - snowfall early this morning will camouflage these fresh drifts and make them hard to identify.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Persistent slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> 1-2 ft deep remain possible across the entire forecast area. A weak layer of facets responsible for this problem is very easy to find in the snowpack. The odds of triggering one of these avalanches are higher on slopes loaded by yesterday’s strong southerly winds. </span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Where to travel</span></span></strong></span></span></span><span><span><span><span><span><span> - The easiest option is to seek out slopes less than 30 degrees in steepness that are not steep enough to slide. Otherwise, if getting onto steeper terrain, choose slopes sheltered from yesterday’s strong winds and have a clean runout with no trees, rocks, or terrain traps that make the consequences of an avalanche worse.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Looking ahead</span></span></strong></span></span></span><span><span><span><span><span><span>, with such a widespread persistent weak layer in the snowpack, the situation will have to get worse before it gets better. More snow coming through this weekend will make persistent slab avalanches more likely and larger, but in the long run can help to bury and heal this weak layer. Be patient and play it safe.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>With two types of avalanches possible today the avalanche danger is MODERATE with heightened avalanche conditions on recently wind loaded slopes</span></span></span></span></span></span></p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
Still Windy in Hyalite
Headed into Blackmore Basin today planning to keep it low angle and to see the effects of recent snow and wind. Moderate winds with strong gusts were transporting snow the entire day, and a stout windslab was widespread. All previous tracks on the main SE facing run were completely filled in. Asides from the wind transport and some small natural cornice drops I noticed no other major signs of instability, but still kept a solid margin from avalanche terrain.