GNFAC Avalanche Forecast for Fri Mar 29, 2019
<p>The recent storm was a bit of a letdown, but did drop enough fresh snow to bump up the avalanche danger. Today, instabilities will be confined to the new snow. Dry loose avalanches will move easily on the frozen old snow surface. These won’t pack a Mike Tyson type of punch, but they could be problematic if they catch you off guard. Wind slabs won’t be widespread, but may be encountered below ridgelines loaded by westerly winds (<strong><a href="https://www.mtavalanche.com/images/19/wind-slabs-hyalite-2">photo</a></…;). Watch for and avoid any steep slope that appears recently wind loaded, especially those in higher consequence terrain.</p>
<p>If the sun pokes out this afternoon wet loose avalanches will be possible. These will be confined to steep slopes facing south through west (<strong><a href="https://www.youtube.com/watch?v=mpk-8hesFaU&list=PLXu5151nmAvRNl9ku…;). Roller balls and small point releases are clues the surface snow is heating up and becoming unstable. Avoid steep sun exposed slopes if these signs are present. I don’t expect wet loose avalanches to be a major concern today. Outside of new snow instabilities the snowpack is generally strong and stable.</p>
<p>Today, human triggered avalanches are possible and the avalanche danger is rated <strong>MODERATE</strong>.</p>
<p>Big hype is the best way to kill a storm. The mountains near West Yellowstone and Cooke City picked up the low end with only 1-2” of new snow. This dust on crust will do little to heighten the avalanche danger. A skier or rider might find an isolated wind slab below an upper elevation ridgeline, but these will be small and relatively harmless. Yesterday, Alex was in Cooke City and found the new snow to be his primary concern (<strong><a href="https://www.youtube.com/watch?v=-f8al-UsP3s&list=PLXu5151nmAvRNl9ku…;
<p>Aside from isolated new snow instabilities, the snowpack is generally stable. On all but high north facing slopes, a thick crust exists beneath the skiff of new snow (<strong><a href="https://www.mtavalanche.com/images/19/avalanches-confined-new-snow">pho…;). This crust will likely stay intact today producing stable but teeth rattling conditions. Select areas on upper elevation-north facing slopes will provide decent skiing and riding conditions on dry snow.</p>
<p>Today, natural and human triggered avalanches are unlikely and the avalanche danger is rated <strong>LOW</strong>.</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>
Near Cooke City we found a generally stable snowpack, similar to the rest of the advisory area. For the next few days avalanches will be confined to new snow that falls. These slides can be dry or wet loose slides, or fresh wind slabs. Carefully assess the stability of the new snow before riding steep terrain. Photo: GNFAC
GNFAC Avalanche Forecast for Thu Mar 28, 2019
<p>Winter is returning for a quick jab. Mountain temperatures are below freezing and snow is expected. The snowpack is stable: it is either frozen where it was previously wet, or on high elevation, northerly aspects, the snowpack is dry and strong. Our last two field days to the Bridger Range (<u><strong><a href="https://www.mtavalanche.com/images/19/changes-aspect-saddle-peak">photo…;, <u><strong><a href="https://www.youtube.com/watch?v=mpk-8hesFaU&t=0s&index=2&li…;) and Lionhead (<u><strong><a href="https://www.youtube.com/watch?v=C6qgTWYjj7U&list=PLXu5151nmAvRNl9ku…;) confirmed the overall good stability of the snowpack. In our videos we highlighted the differences with aspect and elevation and mentioned the potential problem of new snow sluffing off the frozen crust.</p>
<p>Avalanche activity will be confined to today’s new snow; nothing will break deeper. The snow will easily sluff off the frozen surface and travel fast and far down the slope. Winds are expected to pick up and minor wind-drifting is possible. Of course, both these concerns only come into play <u>if it snows</u>. We have generally safe avalanche conditions and generally poor skiing and riding, unless of course you enjoy frozen chicken heads, then you’ll be in heaven.</p>
<p>For today, the avalanche danger throughout our forecast area is <strong>LOW</strong>.</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>
GNFAC Avalanche Forecast for Wed Mar 27, 2019
<p>Both wet and dry avalanches are unlikely today. Conditions are a hodge-podge of wet snow at lower elevations and frozen, rattle-your-teeth-out chunks, fondly referred to as chunder, on upper elevation slopes that were previously wet from the sun. Yesterday, Eric and our intern Andrew skied down the west and east sides of the Bridger Range and encountered it all: dry snow, wet snow and chunder. Small changes in aspect and elevation had dramatic effects on the snowpack with dry conditions on more high and northerly and wet on anything southerly (<strong><a href="https://www.mtavalanche.com/images/19/changes-aspect-saddle-peak">photo…;, <strong><a href="https://www.youtube.com/watch?v=mpk-8hesFaU&t=0s&index=2&li…;). This is similar to what Ian and I found in Lionhead on Monday (<strong><a href="https://www.youtube.com/watch?v=C6qgTWYjj7U&list=PLXu5151nmAvRNl9ku…;
<p>Most of our avalanche concerns have been with wet avalanches, but yesterday at upper elevations in Hyalite skiers triggered small, dry wind slabs on slopes that were cross-loaded (<strong><a href="https://www.mtavalanche.com/node/20515">details</a></strong>). Today, our avalanche concern is confined to new snow and wind-drifted snow, which is not much of problem since snow showers are predicted to be light. This may change tomorrow, but right now the avalanche danger throughout our forecast area is rated LOW.</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>
Skier triggered small wind slab
From an email: "Small cross loaded slopes were easy to trigger. None were very large, but I did kick off numerous small windslabs on multiple aspects. Some large cornices were starting to detach from ridges along Mt. Bole and in the Maid of the Mist area. Numerous had fallen recently and created sizable debris piles. Attached is a picture of one of the cross-loaded ribs that I triggered while skinning by."
A skier in Hyalite found small but easy to trigger wind slabs at upper elevations near Mt. Bole in Hyalite. Photo: C. Kussmaul
A skier in Hyalite found small but easy to trigger wind slabs at upper elevations near Mt. Bole in Hyalite. Photo: C. Kussmaul