"A 4-14" deep by 30ft wide slab released naturally? below dry martha, we think this morning (1/3/19). it ran approx 300ft over the bottom cliff and stopped near the south bowl traverse." Photo: BBSP
Extreme whoomphing while breaking trail along Bear Basin yesterday. Extremely faceted snow forming and producing unstable snowpack about a foot+ deep. Andrew Belli
<p>Weak faceted snow near the ground continues to make avalanches possible. Yesterday, my partner and I toured around Bacon Rind in the southern Madison Range and experienced large collapses and unstable test results (<strong><a href="https://www.youtube.com/watch?v=zj26vpS2WE0">video</a></strong>). After feeling and hearing entire slopes collapse under our feet, we avoided all slopes steeper than 30 degrees. Although conditions are less touchy than they were earlier in the week (<u><strong><a href="https://www.youtube.com/watch?v=1Z5eDFItVF4&t=0s&index=2&li…;, <u><strong><a href="https://www.mtavalanche.com/images/19/natural-avalanche-lionhead-ridge"…;), I would still suggest avoiding avalanche terrain.</p>
<p>Today, weak facets near the ground capped by a cohesive slab make avalanches possible. For this reason the avalanche danger is rated <strong>MODERATE</strong>.</p>
<p>Strong winds the past few days have hit all aspects and elevations. Some slopes are stripped and scoured while others are heavily loaded. Watch for thick wind drifts below ridgelines, rock outcroppings, and cross loaded terrain features. Not all wind loaded slopes will be touchy to human triggers. However, avalanches remain possible on slopes where wind deposited snow rests over lower density new snow or faceted layers. Today, carefully assess wind loaded slopes before traveling in avalanche terrain. On upper elevation slopes, a strong snowpack will keep instabilities confined to new and wind-blown snow.</p>
<p>On mid to low elevation slopes, a shallow and weak snowpack continues to produce signs of instability (<u><strong><a href="https://www.youtube.com/watch?v=jnXlxSi2MRE&list=PLXu5151nmAvRNl9ku…;, <u><strong><a href="https://www.mtavalanche.com/images/19/buried-facets-wilson-peak">photo<…;). Yesterday, a skier experienced collapsing on a southwest facing slope near Mt Blackmore. Triggering a slide on buried persistent weak layers is becoming less likely without a recent loading event, but is something to consider when traveling on slopes with a shallow and weak snowpack.</p>
<p>Today, human triggered avalanche are possible and the avalanche danger is rated <strong>MODERATE</strong>.</p>
<p>Without a recent loading event, the snowpack is trending towards stability. The primary avalanche concern will be slopes that got heavily wind loaded earlier in the week (<u><strong><a href="https://www.mtavalanche.com/images/19/crown-butte-avalanches-1">photo</…;). These slopes have had time to gain strength, but still need to be evaluated carefully. Watch for thick wind drifts in exposed terrain loaded by west-northwest winds. Be especially aware of this problem on slopes with terrain traps such as gullies, rock bands, or thick trees. It’s important to remember that small slides can have severe consequences. Outside of wind loaded slopes the snowpack is generally stable.</p>
<p>Today, heightened avalanche conditions exist on wind loaded slopes which have a <strong>MODERATE</strong> avalanche danger. Non-wind loaded slopes have a <strong>LOW</strong> avalanche danger.</p>
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
BOZEMAN
January 8, Women’s Specific Avalanche Awareness, 6:30-8 p.m. Story Mill Park, Bozeman.
January 9, 1-hr Avalanche Awareness, 7-8 p.m. Spire Climbing Center, Bozeman.
<p>A well-developed layer of facets forms the foundation of the pack on most slopes in the southern Madison Range and mountains near West Yellowstone (<u><strong><a href="https://www.youtube.com/watch?v=MeTYd9mOyGk&list=PLXu5151nmAvRNl9ku…;). This persistent weak layer was put under significant stress earlier in the week when it was loaded by 12-18” of new snow. On Tuesday, Doug rode in the Lionhead area and observed numerous natural avalanches that occurred during or immediately after the storm (<u><strong><a href="https://www.youtube.com/watch?v=1Z5eDFItVF4&t=0s&index=2&li…;, <u><strong><a href="https://www.mtavalanche.com/images/19/natural-avalanche-lionhead-ridge"…;). Since the storm ended on Monday, the snowpack has some time to adjust. Avalanches won’t be as easy to trigger today, but they still remain possible. All steep slopes should be considered suspect and approached with caution. It will be possible to remotely trigger slides from low angle or flat terrain. Keep in mind, if a slide does occur it will fail near the ground and likely be a large and dangerous.</p>
<p>Today, human triggered avalanches are possible and the avalanche danger is rated <strong>MODERATE</strong>.</p>
<p>There are two different scenarios going on in the mountains around Bozeman and Big Sky. In upper elevation terrain, the primary avalanche concern is wind loaded slopes. Areas loaded by west-northwest winds are the most likely to hold unstable conditions. Recently wind loaded slopes won’t be hair trigger, but still hold the potential to produce human triggered avalanches. Watch for rounded, firm pillows of wind drifted snow and approach these areas with caution. Fortunately, the snowpack lacks persistent weak layers at upper elevations, which will keep instabilities confined to new and wind-blown snow.</p>
<p>The second scenario is a shallow and weak snowpack on lower elevation slopes. Weak facets near the ground are now loaded by up to a foot of fresh snow. Widespread cracking and collapsing have been reported on Mt Ellis, Mt Wheeler, and lower terrain near Big Sky (<strong><a href="https://www.youtube.com/watch?v=jnXlxSi2MRE&list=PLXu5151nmAvRNl9ku…;, <strong><a href="https://www.mtavalanche.com/images/19/buried-facets-wilson-peak">photo<…;). This is a clear indication unstable conditions exist where the snowpack is shallow and weak. Watch for signs of instability such as cracking/collapsing and avoid steep terrain where these signs are present.</p>
<p>Today, wind loading and weak layers make human triggered avalanches possible and the avalanche danger is rated <strong>MODERATE</strong>.</p>
<p>The storm over New Year’s did not produce much avalanche activity around Cooke City. A few small natural avalanches were observed on wind loaded slopes (<u><strong><a href="https://www.mtavalanche.com/images/19/crown-butte-avalanches-1">photo</…;), but in general the snowpack handled the load quite well. Although winds have been light the past few days, slopes loaded earlier in the week could still produce avalanches under the weight of a skier or rider. Watch for wind loaded slopes below ridgelines and cross loaded terrain features. </p>
<p>A secondary, but not widespread problem involves facets buried mid-pack and near the ground (<u><strong><a href="https://www.youtube.com/watch?v=W6iS9ManzPo&index=2&list=PLXu51…;, <u><strong><a href="https://www.mtavalanche.com/images/18/instability-near-lulu-pass">photo…;, <u><strong><a href="https://www.youtube.com/watch?v=4Vb2Y4UZJ1Q&index=2&t=0s&li…;). These layers have not been highly reactive, but are worth assessing before jumping into avalanche terrain.</p>
<p>The snowpack is trending towards stability, but avalanches remain possible on wind loaded slopes which have a <strong>MODERATE</strong> avalanche danger. Generally safe avalanche conditions exist on non-wind loaded slopes which have <strong>LOW</strong> avalanche danger.</p>
<p>If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u>, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
BOZEMAN
January 8, Women’s Specific Avalanche Awareness, 6:30-8 p.m. Story Mill Park, Bozeman.
January 9, 1-hr Avalanche Awareness, 7-8 p.m. Spire Climbing Center, Bozeman.
Skiers reported collapsing on their approach to Wheeler Mountain. From the email: " Within the the first 50 vertical feet ascending, we experienced two significant collapses/ ‘whumphing’. No signs of avalanche from the previous party’s fun looking tracks."
