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GNFAC Avalanche Forecast for Wed Oct 30, 2024

Snowpack and Avalanche Discussion

The mountains are turning white which means avalanche season is here. There is 0-8” of settled snow at weather stations and many slopes have grass and rocks poking through or are still bare ground. However, there is a slightly deeper snowpack on high elevation, shady slopes, especially where snow from earlier storms was drifted deeper in gullies and near ridgelines. These slopes are where you could find a layered snowpack and trigger an avalanche.

Watch out for steep slopes where recent snow has drifted into a slab on top of older snow. Because few slopes exist with a deeper snowpack, they are not only the most likely place to trigger an avalanche, but also the most attractive place to ski or ride. A scary combination. Avalanches of wind-drifted snow will be shallow and generally small, but even small slides can injure or be fatal, especially if they drag you into rocks, trees, over cliffs or pile up deep in a confined gully.

Early season avalanches in southwest Montana have seriously injured and buried skiers (<a href="https://www.mtavalanche.com/accident/12/10/31"><stron… Incident Report</a>), caught and injured hunters (<a href="https://www.mtavalanche.com/accident/15/11/06"><stron… Incident Report</a>), and resulted in tragic fatalities (<a href="https://www.mtavalanche.com/accident/17/10/12"><stron… Incident Report</a>).

Whether you are skiing, hunting, ice-climbing or hiking you should consider the potential for avalanches if you travel on snow covered slopes. Choose slopes less than 30 degrees steep to avoid being in avalanche terrain, or carefully assess the snowpack for unstable drifts before riding or crossing steep slopes.

Remember the basics of avalanche safety if you plan to travel on snow-covered slopes.

<ul>
<li>Beacons, shovels and probes are requisite equipment for each party member. Helmets and airbags are excellent additions.</li>
<li>Only expose one person at a time to avalanche terrain (<a href="https://www.youtube.com/watch?v=_d5_vlY-bjg"><s… steeper than 30 degrees</a>) while partners look on from a safe area nearby.</li>
<li>Watch for red flags that indicate instability, such as recent avalanche activity, cracking and collapsing. If these are present, avoid steep slopes. </li>
<li>If there is enough snow to ride, there is enough snow to slide. Dig down and test the snowpack for instability before considering travel in avalanche terrain.</li>
</ul>

Before you get out this season, check over your avalanche gear (<a href="https://youtube.com/watch?v=Izkv4IIUmbk"><spa…;), refresh your skills by practicing avalanche rescue with your backcountry partners (<a href="https://www.youtube.com/watch?v=p1xuaaSq4YU">…;) and sign up for an avalanche class. Our <a href="https://www.mtavalanche.com/workshops/calendar"><stro… calendar</a> lists local courses the Friends of the Avalanche Center and other regional providers offer.

Read more about GNFAC Avalanche Forecast for Wed Oct 30, 2024

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Weather and Avalanche Log for Wed Oct 30, 2024

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Weather and Avalanche Log for Tue Oct 29, 2024

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Blackmore early season

Date

Mon, 10/28/2024 - 09:55

Activity

Snowshoeing

From e-mail: "I went for a quick run up to Blackmore yesterday afternoon/eve (10/21) to have a look at the snow.

Brief summary:

-snow on SSE-S-SW-W had melted off completely, but as soon as I wrapped to SE or NW there was still an appreciable amount of snow, with dry gaps forming between snow patches.

-E-NE-N (and flat terrain) had settled HS of 15-20cm at 8,500' and 25-30cm by 9,500'. The snow here formed a thick blanket over the terrain, covering/smoothing a lot of the roughness. All of the snow I encountered had either an ambient melt-freeze crust on the surface (thin, pencil hard), or a thicker sun crust (depending on aspect, a bit thicker, pencil hard). Presumably these crusts had melted during the day (and the previous days) but were already refreezing by late afternoon. Underneath the crusts the snow was dense, moist to wet, and quite homogenous, though I could make out some graupel grains without obvious layering at the upper end of my traveled elevation (summit, ~10,150').

-Right now the snow on the ground looks lovely! Moist/wet, dense, homogenous, filling in terrain roughness, etc. As it sits, this would make an excellent base. There is a lot of potential for strong gradients and facet development at/near the surficial crust, but the temps have been so mild that this hasn't been an issue yet (where I observed the snow). Looking into the future, we may get colder temps next week and a dusting of snow on top of the current snow... this would be a great way to turn a nicely developing base into an ugly weak layer, but only time will tell... As far as skiability goes, a lot of the terrain that is holding snow now would quickly become skiable with a decent storm on top. Still dangerous from rocks/stumps/etc, but definitely skiable.

-Ice: I didn't go into the main fork, but based on observations it seemed like it has been too warm for much/any ice to be forming. Tons of water moving through the landscape though, just need some cold. Also, there is a ton of snow down on the Sphinx (marginal photo below), I bet that comes in quickly when we get overnight freezes."

Region

Northern Gallatin

Location (from list)

Mt Blackmore

Observer Name

Ben VandenBos

Weather and Avalanche Log for Mon Oct 28, 2024

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@0700

Weather and Avalanche Log for Sun Oct 27, 2024

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Weather and Avalanche Log for Sat Oct 26, 2024

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GNFAC Avalanche Forecast for Thu Oct 24, 2024

Snowpack and Avalanche Discussion

While most slopes are still bare ground and have no avalanche hazard, there is now some snow in the mountains and that requires considering the potential for avalanches. Treat every steep, snow covered slope as suspect until proven otherwise.

Slides are most likely where wind-loaded snow drifts more deeply in gullies and near ridgelines. Getting caught and carried at this time of year has the added consequence of bouncing off rough underlying surfaces, including rocks and stumps. Early season avalanches in southwest Montana have seriously injured and buried skiers (<a href="https://www.mtavalanche.com/accident/12/10/31"><stron… Incident Report</a>), caught and injured hunters (<a href="https://www.mtavalanche.com/accident/15/11/06"><stron… Incident Report</a>), and resulted in tragic fatalities (<a href="https://www.mtavalanche.com/accident/17/10/12"><stron… Incident Report</a>).

Remember the basics of avalanche safety as we begin traveling on snow-covered slopes.

<ul>
<li>Beacons, shovels and probes are requisite equipment for each party member. Helmets and airbags are excellent additions. </li>
<li>Only expose one person at a time to avalanche terrain (<a href="https://www.youtube.com/watch?v=_d5_vlY-bjg"><s… steeper than 30 degrees</a>) while partners look on from a safe area nearby. </li>
<li>Watch for red flags that indicate instability, such as recent avalanche activity, cracking and collapsing. If these are present, avoid steep slopes. </li>
<li>If there is enough snow to ride, there is enough snow to slide. Dig down and test the snowpack for instability before considering travel in avalanche terrain.</li>
</ul>

Read more about GNFAC Avalanche Forecast for Thu Oct 24, 2024

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Weather and Avalanche Log for Thu Oct 24, 2024

Read more about Weather and Avalanche Log for Thu Oct 24, 2024

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