19-20

GNFAC Avalanche Forecast for Sun Mar 15, 2020

Snowpack and Avalanche Discussion

<p>Over the last 24 hours the mountains near Cooke City, West Yellowstone, the southern Madison and southern Gallatin Ranges received 8-10” of snow equal to 0.8-1.1” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE). Avalanche danger will increase today with more snow and moderate winds. Avalanches can easily be triggered in the new snow, especially where it is drifted into thicker slabs by southerly&nbsp;winds. Keep terrain choices simple and not overly committing. Avoid wind loaded slopes, and carefully assess the stability of the new snow. Avoid all steep slopes if the new snow cracks or slides easily, or if you see natural avalanches. Today continued snowfall creates dangerous avalanche conditions and avalanche danger is rated CONSIDERABLE on wind loaded slopes and MODERATE on all other slopes.</p>

<p>Near Bozeman and Big Sky the mountains got 2-5” of snow equal to 0.2-0.5” of SWE. Avalanches are possible to trigger where moderate wind drifts this snow into fresh slabs. Today carefully evaluate wind loaded slopes. Be cautious of fresh drifts and avoid terrain where they can push you into trees, over cliffs or pile deep in a confined terrain feature. Expect drifts to grow with more snow and wind today.</p>

<p>Cornices are an additional hazard to watch for and avoid (<strong><a href="https://www.mtavalanche.com/images/20/huge-cornices-cooke-city">photo</…;). These overhangs of snow along ridgelines are large and can break back farther than expected. Avalanches breaking deeper in the snowpack are not expected, but a cornice fall could be what it takes to find the weak spot. Stay far back from the edge of ridgelines and avoid slopes directly below large cornices.</p>

<p>Today, avalanches are possible on wind loaded slopes which have a MODERATE avalanche danger. On non-wind loaded slopes avalanche danger is LOW.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an <u><a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a></u>, email us (<u><a href="mailto:mtavalanche@gmail.com&quot; target="_blank">mtavalanche@gmail.com</a></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.

GNFAC Avalanche Forecast for Sat Mar 14, 2020

Snowpack and Avalanche Discussion

<p>The dusting of new snow this morning isn’t enough to elevate the avalanche danger. However, depending on how fast snow accumulates, we may see an increased hazard by this afternoon.</p>

<p>The snowpack is generally stable. Yesterday, Dave rode near Cooke City and covered his bases by avoiding slopes below big cornices but otherwise felt good about stability (<strong><a href="https://www.youtube.com/watch?v=DRGh0aIVrPg&amp;list=PLXu5151nmAvSbcbVf…;). Cornices have grown huge and can break off unpredictably. Minimizing your time beneath them is always a good idea, but especially with the combination of low visibility and active loading that we’ll have today.</p>

<p>The wind slabs that formed earlier this week are mostly bonded and of minimal concern. However, yesterday, skiers in Cooke City dug a snowpit, found a reactive wind slab, and backed off the wind loaded slope they had been thinking about skiing. Follow their example by searching for signs of instability and backing off if you find them.</p>

<p>As snow falls&nbsp;today it will be drifted by strong winds. Fresh wind slabs will build through the day. As they grow they will be easily triggered by skiers or riders. The slabs will start off thin, but may become deep enough to cause issues by later in the afternoon. Adjust your plans if you find fresh wind slabs more than a few inches thick.</p>

<p>Large avalanches are unlikely and the avalanche danger is LOW this morning. Danger may rise to MODERATE by this afternoon on wind loaded slopes if heavy snowfall develops more quickly than expected.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an <a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a>, email us (<a href="mailto:mtavalanche@gmail.com&quot; target="_blank">mtavalanche@gmail.com</a>), 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

TODAY! March 14 (last of the season) Rescue Training at Round Lake stop by anytime between 10-2.