Extreme winds today, intense wind transport. Observed one natural avalanche, SS-N-D1R2-I at 9200 ft, NW aspect. ECTP on N aspect, on the depth hoar, thin spot HS 115 cm at 9600 ft N aspect. Large cornice collapse hit lookers R side of the NF, no deeper slab results. Debris was blown in, hard to say if anything shallower pulled out.
These deep slab avalanches on the E face of Cedar Mountain (and lower flank) likely avalanched Feb 23 or 24.
This deep slab avalanche on the E face of Cedar Mountain likely avalanched in the last day or two (Feb 24). Photo: B. Rode
Ice climbers across Hyalite Canyon near G2 saw a wide and deep crown across the east face of Elephant Mountain.
<p>In the Bridger Range 8” of new snow yesterday morning and 2” during the day all got blown around last night from strong west wind. It blew at all elevations and aspects and loaded slopes which could easily be triggered by a skier or rider. Shooting cracks are bulls-eye data of instability. Once a wind slab is released it could trigger a deeper slide on weak snow near the ground. A safe tactic is to stay off of wind-loaded terrain today. These freshly formed drifts might not be bonded to the underlying snow. The avalanche danger is rated CONSIDERABLE on all wind-loaded slopes and MODERATE on all others.</p>
<p>In the Gallatin and Madison Ranges and Lionhead area, the stability is getting better, but also a bit scarier. With time the snowpack is adjusting to last week’s snow load and triggering avalanches is becoming more difficult. It’s scarier because the weak snow at the ground (depth hoar) has avalanched deep and wide on a few slopes. These big slides, called <em>Deep Slabs</em>, are a bit of a nightmare. A person has low odds of triggering one and high odds of dying if they do. Our videos from 2 field days in <a href="https://youtu.be/65JO-4w4qXo"><strong><u>McAtee Basin</u></strong></a> and <a href="https://youtu.be/C1F9DWC-gfA"><strong><u>Lionhead</u></strong></a> explain the possibility of triggering deep slab avalanches. Yesterday, ice climbers reported a wide and deep avalanche crown on the east face of Elephant Mountain in Hyalite; surprisingly wide and deep avalanches were triggered by Big Sky Snow Safety with explosives; plus deep avalanches on Mt Blackmore last week (<a href="https://youtu.be/Ychm42ihtjk"><strong><u>video</u></strong></a>, <a href="https://www.mtavalanche.com/images/21/natural-avalanche-blackmore-east-…;), in Flanders Creek (<a href="https://www.mtavalanche.com/images/21/natural-deep-slab-flanders"><stro…;) and around Lone Lake Cirque (<a href="https://www.mtavalanche.com/images/21/lone-lake-cirque-avalanche"><stro…;). Last week’s 2-4 feet of snow with 3 days of strong wind almost doubled the depth of the snowpack in some areas. The weak, sugary snow at the ground is avalanching. The recent deep slab natural activity in tandem with avalanche control at the ski area getting wide and deep slides makes me sit up straight and pay attention. Deep slabs are here to stay. These can be triggered from thinner areas (3 feet or less) by the weight of a person. </p>
<p>For today the danger is rated MODERATE on all slopes because triggering avalanches is possible.</p>
<p>Ian just returned from 2 days in Cooke City where he saw a few slides on wind-loaded slopes (<a href="https://youtu.be/-aLItsHjWLI"><strong><u>video</u></strong></a>). The avalanches on Mt. Henderson (<a href="https://www.mtavalanche.com/images/21/wind-slab-avalanche-henderson-mtn…;), the shoulder of Mt. Abundance (<a href="https://www.mtavalanche.com/images/21/natural-avalanche-shoulder-mt-abu…;) and a cornice triggered slide on Wolverine Peak (<a href="https://www.mtavalanche.com/images/21/cornice-triggered-slide-wolverine…;) all involved the new wind-drifted snow. It will remain possible to trigger slides on other wind-loaded slopes, so be wary if you see shooting cracks or notice waves of wind drifts. Also, a few isolated slopes have an unusually thin snowcover and/or rocky terrain are areas of weak snow where someone could trigger a slide. For today the avalanche danger is rated MODERATE on all slopes. </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><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>
The Friends of the Avalanche Center in partnership with the City of Bozeman put in a Beacon Park at Beall Park. It is located on the north side of the Beall building between N. Bozeman Ave. and the ice rink. Stop by with your
This natural avalanche on the SE shoulder of Mt Abundance avalanches regularly from wind-loading. Photo: S. Strenge
This avalanche on the east face of Wolverine Peak outside Cooke City was triggered by a cornice on 24 February. Although it did not propagate wide, it ran far. Photo: S. Strenge
This small natural avalanche broke on a steep, rocky slope in Beaver Creek.
