The wind texture across the south face of Mt. Blackmore is evidence if wind-loading. The 8" of new snow drifted into small slabs near the ridgelines that were reactive to ski cuts. Photo: G. Antonioli
<p>Snowpack depth decreased last week with above freezing temperatures, yet the mountains still hold 2-3 feet of dense, settled snow with up to 6 feet near Cooke City. Fresh snow today will be a welcome improvement to riding and skiing conditions, and the snowpack is mostly stable aside from instability associated with new snow today (<strong><a href="https://youtu.be/BGMeTxj_YcU">video</a></strong>).</p>
<p>Fresh drifts of snow will form near ridgelines and be easy to trigger as they grow today. The size and distribution of these wind slabs will depend on the amount of snow and wind this morning. This instability will likely be short lived, and is easiest to avoid with careful terrain selection for a couple days. Plan to avoid fresh drifts along ridgelines and keep an eye out for unstable drifts along the edge of gullies or the base of cliffs.</p>
<p>Steady snowfall and relatively warm temperatures through October and mid-November created a strong snowpack without widespread weak layers. New snow amounts today near the hopeful forecast of 8-15” will probably not be enough to trigger avalanches deeper than the new snow. However, more new snow creates more instability. Avoid avalanche terrain if you see obvious signs of instability such as cracking and collapsing or natural avalanches. Dig down a foot or two to assess the interface between the new snow and old snow; and look a couple feet below the new snow for isolated deeper instabilities, similar to the unstable results in this <strong><a href="https://www.mtavalanche.com/images/17/pebble-creek-26-nov">snowpit</a><…; or this avalanche last week near Cooke City (<strong><a href="https://www.mtavalanche.com/images/17/natural-avalanche-cooke-city-0">p…;).</p>
<p>New snow this morning makes avalanches possible today and the avalanche danger is <strong>MODERATE</strong>.</p>
<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a>, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Some days the big lines will go, but other days they won't. It's up to you to decide, because the best days are the ones when you return home safely. Three skiers walk through the decision making process in Get Avalanche Smart - Episode 3: The Great One.
<p>Below freezing temperatures and moderate wind the last couple days kept the snowpack frozen and stable. Today is different. Temperatures at 4 a.m. are above freezing up to 9,000’, and the snowpack will become wet, non-cohesive and lose strength.</p>
<p>Wet snow avalanches are possible today and could be triggered on all steep slopes except high elevation, northerly aspects. Recent freezing temperatures formed a thick crust on the snow surface, which will be supportable this morning then melt and soften today. Slopes that allow supportable, easy travel this morning will likely become wet and weak by the afternoon.</p>
<p>Be cautious of terrain overhead such as steep, rocky slopes that hold snow and could avalanche naturally as they warm through the day. If you sink past your boot in wet snow or see obvious signs of instability like pinwheels, roller balls, or natural avalanches, then avoid steep slopes and minimize exposure to runout zones. Wet snow avalanches are possible today and the avalanche danger is <strong>MODERATE</strong>.</p>
<p>A frozen, stable snowpack one day followed by wet, weak snow the next is more typical of April than November. Unusual weather creates unusual avalanches and calls for extra caution. Don’t hesitate to bail early or change plans before obvious signs of wet snow instability are present.</p>
<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a>, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Some days the big lines will go, but other days they won't. It's up to you to decide, because the best days are the ones when you return home safely. Three skiers walk through the decision making process in Get Avalanche Smart - Episode 3: The Great One.
Freezing level above 9,000' at 0400
<p><u>Bridger Range</u> <u>Gallatin Range</u> <u>Madison Range</u> <u>Lionhead area near West Yellowstone</u></p>
<p>Below freezing temperatures overnight have helped stability, but haven’t done much to improve riding conditions. If you do get out today, the snowpack will be firm and locked up tight. On a positive note, there won’t be much in the way of avalanche hazard, though there could be a random wind slab perched precariously under an upper elevation ridgeline. This problem won’t be widespread, but it can’t be entirely ruled out.</p>
<p>Although the avalanche hazard has been minimized with freezing temperatures, it is not the time to throw caution to the wind. Basic avalanche protocol still applies when heading in the backcountry. This includes carrying the proper rescue gear (shovel, beacon and probe), traveling one at a time on steep slopes, and watching your partner from a safe location.</p>
<p>Today, avalanches are unlikely and the avalanche danger is rated <strong>LOW</strong>.</p>
<p>Cooke City has the deepest snowpack in the advisory area. On average, the pack is 4-6’ deep at higher elevations. Earlier in the week, Doug and I traveled in the mountains around Cooke City and found mostly stable snow (<a href="https://www.youtube.com/watch?v=BGMeTxj_YcU&list=PLXu5151nmAvQSYtIf…;, </strong><a href="https://www.mtavalanche.com/images/17/digging-pit-scotch-bonnet"><stron…;). Although warm temps and rain did affect this area, the snowpack has remained cold and dry at higher elevations. Yesterday, a skier observed heavy wind loading caused to strong southwest winds. Today, wind slabs will be the primary avalanche problem. Keep an eye out for wind loaded slopes below upper elevation ridgelines and on the leeward side of cross loaded terrain features.</p>
<p>Today, human triggered avalanches are possible on wind loaded slopes which have a <strong>MODERATE</strong> avalanche danger. Non-wind loaded slopes have a <strong>LOW</strong> avalanche danger.</p>
<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a>, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
<p>Some days the big lines will go, but other days they won't. It's up to you to decide, because the best days are the ones when you return home safely. Three skiers walk through the decision making process in <a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank"><em>Get Avalanche Smart - Episode 3: The Great One.</em></a></p>
BOZEMAN
Nov. 28, Avalanche Awareness, 6-7:30 p.m. at Play it Again Sports
Nov. 29, 30 and Dec. 2, 3 or 9, Introduction to Avalanches w/ Field Day, Info and Register Here
Dec. 6, Avalanche Awareness, 6-7:30 p.m. at REI Bozeman
A skier outside of Cooke City observed this natural avalanche on a NW facing slope around 9,200 ft. By the looks of it, this slide appears to be a wet slab that failed during the period of above freezing temps and rain a few days ago. While the snowpack is mostly stable around Cooke City, this slide is a good reminder that isolated instabilities still exist. Photo: B. Fredlund
