From IG message (4/10/20): "My party and I observed a wet slide off of the s-se facing aspect of the Sphinx today around 1pm." Photo: @laura_delray
19-20
GNFAC Avalanche Forecast for Fri Apr 10, 2020
<p>A big swing in the weather means we’ll be worried about just about every type of avalanche at some point over the next three days.</p>
<p>Today will start off sunny and warm. Many slopes only lightly refroze overnight. Crusts will break down quickly this morning. If you’re sinking more than ankle deep into wet snow it is time to get off sunny slopes or out of steep terrain entirely because the conditions for wet slides are developing. These could be wet loose avalanches or more dangerously, wet slabs. A number of natural and human triggered wet slabs broke over the last few days and they are a possibility once again today (<strong><a href="https://www.mtavalanche.com/node/22698">details</a></strong>, <strong><a href="https://www.mtavalanche.com/node/22693">details</a></strong>, <strong><a href="https://www.mtavalanche.com/node/22688">details</a></strong>). Cornices have also been breaking, so give them a wide berth and minimize your time beneath them (<a href="https://www.mtavalanche.com/images/20/massive-cornices-beehive"><strong…;).</p>
<p>Spring storms usually come with some degree of uncertainty and this one is no different. If the storm really delivers, expect to trigger avalanches within the new snow, especially on wind-loaded slopes where the new snow is drifted into deeper drifts. The faster the new snow falls and the more that it piles up the more dangerous conditions will become. The new snow will also add a (potentially rapid) load to the rest of the snowpack. If new snow starts to really accumulate before the wet snow in the snowpack has a chance to refreeze we may see more wet slab activity tomorrow. The new snow will also add stress to the buried weak layers that are still lurking on high elevation shady slopes and we may see avalanches on these layers as well (<a href="https://www.mtavalanche.com/images/20/buried-surface-hoar-crystal"><str…;, <a href="https://www.mtavalanche.com/images/20/ectp-surface-hoar-s-madison"><str…;, <a href="https://www.mtavalanche.com/images/20/ectp-surface-hoar-mt-ellis"><stro…;).</p>
<p>Don’t push it this weekend. Most avalanches occur during and immediately after a storm. Instability will rise as snow accumulates. You may have been wearing flip-flops yesterday, but it is still avalanche season in the mountains and you’ll need to bring your A-game if you’re headed out.</p>
<p>Please continue to send us your observations. You can fill out an observation form, email us (mtavalanche@gmail.com), leave a VM at 406-587-6984, or Instagram (#gnfacobs). We greatly appreciate your support.</p>
GNFAC Forecaster Chat
Monday, April 13, GNFAC Forecaster Chat: Spring snowpack and travel advice, Live Online w/ Uphill Pursuits @ 6-7 p.m. Link here for details and to join the discussion.
Natural and snowmobile triggered wet slabs near Lionhead
Wet slab near Lionhead. Observed 4/9/2020.
Photo: G. Antonioli
Forecast link: GNFAC Avalanche Forecast for Fri Apr 10, 2020
Wet slab near Lionhead. May have been snowmobile triggered. Observed 4/9/2020.
Photo: G. Antonioli
Forecast link: GNFAC Avalanche Forecast for Fri Apr 10, 2020
Cornice triggered wet slab near Lionhead. Observed 4/9/2020.
Photo: G. Antonioli
Forecast link: GNFAC Avalanche Forecast for Fri Apr 10, 2020
Natural wet slide on Fan Mtn.
Observed 4/9/20 at 3pm. Photo: T. Gittins
Snowmobile triggered slide near Lionhead
From email: "On Tuesday, April 7th my group noticed a s slab avalanche above our route back to the parking lot. The coordinates of the s slide are 44.7184217, -111.3190452. There were snowmobile tracks directly to the right (NW) of the s slide The s slide was considerably wide , more than100 yards."