24-25

Good Stability at Lionhead

Date
Activity
Snowmobiling

We rode up to the old weather station and then to the current weather station, down Airplane Bowl, along the base of the LH Ridge to the head of Targhee Creek and back. There is a 4-5" Thick refrozen crust below 3-5 inches of new snow at upper elevations. At lower elevations, there was less snow, and I suspect more rain, and east winds stripped many of the upper starting zones back down to the melt-freeze crust. 

There was little, if any danger of avalanches today. You may have been able to find an isolated wind slab from the east wind-loading, but it would have been small in area and depth. We rode out at 2 PM and the crust had not started breaking down in any meaningful way. 

Tomorrow is supposed to be 8-10 degrees F warmer, but cold temperatures tonight should refreeze the crust, and it is pretty robust. There may be a few very small, wet snow avalanches in the recent snow with warming temperatures, but I would not be particularly worried about slides. There is more snow and colder temps forecast for Sunday and Monday. Fingers crossed for a bit more powder riding. 

The road from the Buttermilk TH was reasonable but is melting out quickly. There were a few dirt patches that will grow tomorrow. 

Beautiful day to spend in the mountains and the riding through the upper bowls was quite nice. 

Region
Lionhead Range
Location (from list)
Lionhead Ridge
Observer Name
Dave Zinn

GNFAC Avalanche Forecast for Fri Apr 18, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Today’s avalanche concerns are all going to within the 5-9” of new snow that fell since Wednesday morning.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Wind Slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are the primary concern. The new snow has been drifted into cohesive slabs by north and east winds since snowfall began. With an easterly component to the winds, be on the lookout for drifts in unusual locations. Some of these drifts will be easily triggered today and some will have already started to bond. Steering around the deepest wind drifts is an easy way to avoid much of the avalanche hazard today. You can also quickly dig down to check how well they’ve bonded to the old snow surface. Cracks shooting out in front of your skis or sled are clear signs you’ve found an unstable drift.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>With clear skies today, the new snow will get wet on sunny slopes and you’ll be able to trigger </span></span></span></span></span></span><span><span><span><strong><span><span>Wet Loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span>. These slides will run on top of the hard crusts underneath the recent snow. Feel for the snow surface getting wet and sticky and look for rollerballs and pinwheels as clear signs that Wet Loose avalanches are imminent. Most of these slides probably won’t have enough volume to bury you, but they can still be surprisingly powerful, plenty strong enough to push you off a cliff or into rocks. Plan to move off steep sunny slopes later in the day, as the snow gets wet.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>With both wet and dry avalanches possible, the avalanche danger is MODERATE today.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>With little new snow and a firm, solidly refrozen crust underneath, avalanches are unlikely and the avalanche danger is LOW. </span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Look out if you find more than a skiff of new snow, in which case you might be able to trigger small Wind Slab or Wet Loose avalanches.&nbsp;</span></span></span></span></span></span></p>

GNFAC Avalanche Forecast for Thu Apr 17, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> will be the most likely slides to trigger today. With gusty east winds this morning and stronger north-northeast winds expected today, wind slabs will grow larger and easier to trigger as the day progresses. HEADS UP - easterly winds will create abnormal loading patterns.</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Storm slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> will be something to consider especially as more snow accumulates. The storm is</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> this morning which is good thing. Today, brief periods of higher snowfall rates or a little bit of warming could create a slightly cohesive slab in the new snow. Look for signs of instability in the new snow by looking for cracking, jumping on small test slopes, and stepping above your partner’s tracks. At a minimum expect sluffing of the new snow.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today the avalanche danger is CONSIDERABLE on wind loaded slopes. Seek out soft powder on slopes untouched by the wind where the danger is MODERATE. Assess stability in the new snow before getting into steeper terrain.</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> will also be a concern in the Gallatin and Madison Ranges but with less new snow they will be shallower. Otherwise, riding slopes untouched by winds may be “dust on crust” and there will only be minor sluffing of the new snow on the hard icy surface underneath.&nbsp;</span></span></span></span></span></span></p>

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

<p><span><span><span><span><span><span>With the snowpack refrozen and no new snow this morning, skiing and riding conditions will be a bit rugged. Avalanches are unlikely and the avalanche danger is LOW.</span></span></span></span></span></span></p>

Deep creek

Date
Activity
Skiing

Toured out Deep Creek to Zeppo’s. Summer trail was largely melted out in the drainage. Despite warm temps and sticky, wet snow on E-S-W aspects, we still found about 4-10 inches of dry new snow over a MF crust on N aspects above 8500 feet. Snow in the Zeppo’s burn was holding up surprisingly well from the previous night’s freeze and was supportable through the afternoon. Large cornice formation on E aspects. 

Region
Out of Advisory Area
Location (from list)
Town Hill
Observer Name
E. Donahue

GNFAC Avalanche Forecast for Wed Apr 16, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>The main avalanche concern today is </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span>. Temperatures did not drop to freezing in many areas overnight, so the snowpack will have a thin refrozen crust only an inch or two thick at most, if at all. Any crusts will melt quickly with sunshine and warm temperatures before clouds move in this afternoon, and it will be possible to trigger wet loose avalanches on steep slopes, especially those that receive direct sunshine. Natural avalanches might initiate near rock outcrops</span></span></span></span></span></span><span><span><span><strong><span><span> </span></span></strong></span></span></span><span><span><span><span><span><span>on steep, sunny slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Without a good refreeze overnight there is potential for some larger wet loose avalanches. Even small avalanches will pose a threat where they can push you over cliffs, into rocks, or carry you down a long steep slope.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Assess the snow surface for wet snow instabilities, and plan to be off and out from under steep, sunny slopes before the sunshine further weakens the snow surface. Any rain this afternoon could also further weaken the snow surface. If you plan to travel on steep slopes, look for shadier slopes with a thicker refrozen crust or dry snow. Sinking past your ankle in wet snow, or seeing rollerballs, pinwheels or natural avalanches means it is time to find lower angle terrain or slopes with a colder, dry or refrozen snow surface.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near Cooke City, you may encounter isolated unstable wind drifts on upper elevation slopes where snow surfaces remain soft and dry.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Also, be cautious on slopes below </span></span></span></span></span></span><span><span><span><strong><span><span>large overhanging cornices</span></span></strong></span></span></span><span><span><span><span><span><span> and give cornices space while traveling on ridgelines above, as they have become weak and easier to break from the heat and sunshine.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The main concern are wet snow avalanches on sun-exposed slopes where a few large avalanches are possible. Assess the snow surface for wet snow instabilities and isolated drifts, especially in steep consequential terrain. The avalanche danger is MODERATE.</span></span></span></span></span></span></p>

Hyalite Road Closure 

The Hyalite Canyon Road is closed to ALL MOTORIZED VEHICLES until May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed.

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