24-25

Storm Snow in the Centennial Range

Date
Activity
Snowmobiling

From phone call:

Kevin took a group into the Centennials.

8" of new snow at 8000'. Surface crust below the new snow was 3 CM thick. There was a facet layer below crust that was concerning. ECTN3 below crust. 

Kevin found the January facet layer 90 CM down (4F hardness) a couple miles north of White Elephant at 7800-7900' (0.5-1mm size). No results in tests but was concerned about their activation if the storm snow start stacking up.  

He noted that the Wind Slab and Storm Slab problems are growing. He saw shooting cracks in the new snow, several feet in front of his skis. 

Winds were light to moderate but gusting into the 20s mph. 

Region
Island Park
Location (from list)
Sawtelle Peak
Observer Name
Kevin Allred

Pinwheels on the flats!

Date
Activity
Snowmobiling

The winds were strong enough combined with the higher humidity snow that pinwheels were actively forming and moving on flat to slightly downhill terrain. I hadn’t seen this often, so I thought it was worth sharing. 

Region
Lionhead Range
Observer Name
Travis Hansen

GNFAC Avalanche Forecast for Thu Mar 13, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Strong winds from the south will whip around the new snow forming fresh </span></span></span></span></span></span><span><span><span><strong><span><span>WIND SLABS</span></span></strong></span></span></span><span><span><span><span><span><span> that will be easy to trigger. They will start small and easily become a foot deep by midday near ridgelines exposed to the wind.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The new snow will be mostly</span></span></span></span></span></span><a href="https://avalanche.org/avalanche-encyclopedia/#right-side-up-storm"><spa…; right-side up</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> but periods of heavier snowfall may create subtle layers in the new snow causing soft </span></span></span></span></span></span><span><span><span><strong><span><span>STORM SLAB AVALANCHES</span></span></strong></span></span></span><span><span><span><span><span><span> on slopes sheltered from the wind. </span></span></span></span></span></span><span><span><span><span><span><u><span><span>Clues</span></span></u></span></span></span></span></span><span><span><span><span><span><span> that storm slabs are becoming a problem include: snow amounts approaching a foot, heavy snowfall rates, and cracking in the new snow.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Near West Yellowstone</span></span></strong></span></span></span><span><span><span><span><span><span> a weak layer of facets buried 2-3 ft deep has been dormant. These probably won’t be an issue today, but could wake up in coming days and cause persistent slab avalanches as new snow stacks up. The last of these slides occurred about two weeks ago.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today with wind and periods of heavy snow the danger will be rising to CONSIDERABLE on wind loaded slopes. The danger on non-wind loaded slopes will rise to MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In areas closer to Big Sky, snow has already started, and strong south winds will be forming shallow </span></span></span></span></span></span><span><span><span><strong><span><span>wind slabs</span></span></strong></span></span></span><span><span><span><span><span><span>. In areas further north, not much snow may fall until after winds start dying down and there will be minimal wind slab formation.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today the avalanche danger is MODERATE. Look for and avoid fresh wind slabs and drifts.</span></span></span></span></span></span></p>

<p>&nbsp;</p>

Upcoming Avalanche Education and Events

Avalanche awareness focused on springtime avalanche conditions: TODAY, March 13 at the Bozeman REI from 6-7:30 p.m.

Texas Meadows

Date
Activity
Skiing

Toured into Texas Meadows this morning. No avalanche activity seen, no cracking or collapsing. Northern aspects and higher elevations holding better snow, without a wind or sun crust.

Region
Bridger Range
Location (from list)
Texas Meadow
Observer Name
C. Robinson

GNFAC Avalanche Forecast for Wed Mar 12, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>It’s getting harder to find soft snow as a result of warm temperatures and very strong winds. It’s also unlikely to trigger an avalanche. While skiing in the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34568"><span><span><span><span><span><… yesterday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, my partner and I found very hard drifts and wind slabs that seemed welded into place. However, we skied around them because I don’t like messing with avalanches.</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Wind slabs</span></span></strong></span></span></span><span><span><span><span><span><span> will be the main thing to steer clear of today. Despite recent very strong winds, they have moved minimal snow as Ian found in the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34571"><span><span><span><span><span><… Bridgers yesterday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. Seek out soft snow on shady slopes untouched by wind for the safest and best riding conditions.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near West Yellowstone, a </span></span></span></span></span></span><span><span><span><strong><span><span>persistent slab </span></span></strong></span></span></span><span><span><span><span><span><span>avalanche problem is mostly dormant. However the weak layer of facets 2-3 feet deep may start to wake up sometime in the near future if enough snow piles up.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today the avalanche danger is LOW.</span></span></span></span></span></span></p>

Upcoming Avalanche Education and Events

Avalanche awareness focused on springtime avalanche conditions: Thursday, March 13 at the Bozeman REI from 6-7:30 p.m.