24-25

Weather and Avalanche Log for Fri Mar 28, 2025

Read more about Weather and Avalanche Log for Fri Mar 28, 2025

Air temps above freezing near Bozeman

Below freezing everywhere else

Snowing on wet snow - 28 March 2025

Read more about Snowing on wet snow - 28 March 2025

Wet Snow in the Southern Madison

Date

Fri, 03/28/2025 - 14:15

Activity

Snowmobiling

We rode into the Taylor Fork, up to the weather station, and out towards the wilderness boundary. Temperatures were around 40 degrees at the car. There was a surficial refreeze last night with a skiff of graupel on top. With mostly sunny skies and calm winds the snow surface dampened quickly.

We dug down on two sunny aspects (E-SE) and noted moist snow throughout the snowpack. In our first snowpit (9220', HS:108) we did not get notable test results (ECTX). We found that although faceted snow remains at the base of the snowpack, water has percolated down and moistened these basal layers.

We also dug on a NW aspect (8800', HS:199) with no notable test results (ECTX). Moist snow exists in the upper 1.5' of the snowpack with dry snow to the ground.

We noted no cracking or collapsing. We saw a good number of wet-loose avalanches on steep sunny slopes, but all were relatively small in width and depth.

Region

Southern Madison

Location (from list)

Taylor Fork

Observer Name

H. Darby

Limited re-freeze in Southern Bridgers

Date

Thu, 03/27/2025 - 10:30

Activity

Skiing

We skied Saddle as early as we could after the lifts opened, but we were still a bit late, and/or there was limited overnight refreeze, I suspect more of the latter. Clear-ish skies overnight had me optimistic, but warms temps seem to have dominated below 9000 ft.

The first 100 vertical feet from the summit skied quite well where a thin melt-freeze crust was just starting to break down. Overcast skies and L-M winds likely limited warming. Below 9000 ft we poked around and found the top 15-20cm was moist and unsupportive on NE-SE aspects. We kicked off numerous roller balls but no actual loose wet avalanches.

The best skiing was in previously skied areas, such as the guts of going home chute, or in-bounds.

Region

Bridger Range

Location (from list)

Saddle Peak

Observer Name

N. deLeeuw

GNFAC Avalanche Forecast for Fri Mar 28, 2025

Snowpack and Avalanche Discussion

Wet loose avalanches are the primary concern today. Cooler temperatures this morning and lower forecasted high temperatures make me a bit less concerned about wet snow today, but we’re not completely out of the woods yet.

Cloudy skies overnight and above freezing air temperatures mean that there will only be a thin crust, if any, on the snow surface this morning. In some areas the snowpack hasn’t refrozen in two or three days. High temperatures aren’t supposed to be quite as crazy as they’ve been the last couple days, but they will still be quite warm. If the sun does come out from behind the clouds this morning (as forecasted), melting will begin rapidly and any crust that did form overnight will quickly start to break down.

Stay on alert for signs of wet snow. If you’re travelling on top of a firm crust, wet snow concerns are minor. If you’re breaking through into wet glop, that means it’s time to get off steep slopes. Pay attention to what’s above you, as one of the main threats of wet loose avalanches is having one start naturally above you, often from near exposed rocks.

Snow on shady slopes at high elevations has stayed cold and dry, but you’ll have to really hunt to find soft snow today.

Avalanche danger is MODERATE.

Much cooler temperatures (below freezing in most places this morning) mean that wet loose avalanches are only a minor concern. Pay attention if you’re breaking through surface crusts into wet snow. In general, I expect the snowpack to be on its way towards refreezing and locking up. Sunshine this morning may melt the snow surface a bit, but I anticipate any wet loose sluffs to be small and only a concern in the most exposed terrain.

The snowpack is generally stable. You might be able to find a wind slab somewhere that hasn’t completely bonded yet, but after days of warm temperatures this concern is also isolated at best.

Tooth rattling riding conditions and the potential for long falls on firm, refrozen surfaces are likely the real primary hazards today.

Large avalanches are unlikely and the avalanche danger is LOW.

Read more about GNFAC Avalanche Forecast for Fri Mar 28, 2025

Weather and Avalanche Log for Thu Mar 27, 2025

Read more about Weather and Avalanche Log for Thu Mar 27, 2025

Air temps above freezing

Clear skies

GNFAC Avalanche Forecast for Thu Mar 27, 2025

Snowpack and Avalanche Discussion

Wet loose avalanches are the main concern today. Ian describes it well in his <a href="https://www.mtavalanche.com/node/34766"><… from yesterday in the northern Bridgers</a> with aspect, elevation, and timing the three variables to consider. With above freezing air temperatures overnight, the snowpack will only have a superficial refreeze from clear skies. As soon as the surface crust melts, wet sluffs will be possible.

Pay attention to what’s above you. One of the main threats of wet loose avalanches isn’t triggering one, but having one start naturally above you, often near exposed rocks. Another significant concern are large CORNICES which are more likely to break spontaneously during rapid warm-ups.

Today, I’d only consider riding sunny slopes (east, south, and west) this morning just as they begin to warm and soften. I’d mostly be aiming for upper elevation north facing slopes that still have dry snow. Old wind slabs should mostly be stabilized, but the threat never goes away  completely.

In the Lionhead area, southern Gallatin and Madison Ranges, and mountains near Cooke City to a lesser extent, there is a slight chance of triggering a persistent slab avalanche. I’d investigate the snowpack about 3 feet deep especially if going into more extreme terrain where the margin for error is narrow. A slide spotted <a href="https://mtavalanche.com/node/34742"><s… days ago on the Fin above Cooke City </a>is a good example of this problem.

The avalanche danger today is MODERATE with wet avalanches an issue on slopes receiving direct sunshine at all elevations and shady slopes below treeline where the snowpack is mostly wet.

Read more about GNFAC Avalanche Forecast for Thu Mar 27, 2025

Wet Loose Avalanches in Airplane Bowl

Fairy Lake

Bridger Range

3/26/2025

Code

WL-N-R1-D1-I

Elevation

8500

Aspect Range

S-SE-E

Latitude

45.90430

Longitude

-110.95800

Notes

We rode up to Fairy Lake area today and quickly found out just how warm it has been in this area the last two days. At the trailhead at 10am temperatures were around 47 degrees. Last night, it did not freeze below 9000' and an isothermic snowpack now exists from the trailhead all the way to Fairy Lake and above, until you pop out into Airplane Bowl. When we returned to the trailhead around 2:30pm, it was 65 degrees at the truck.

While higher elevation southerly and easterly snowpacks were warm and wet, free water was only moving through the upper few inches of the snowpack by 1pm. High elevation northerly aspects remained colder and more locked up than we expected given the ambient air temperature. Winds were light from the W and were doing little to keep surfaces cold.

There were a number of wet loose avalanches in Airplane Bowl when we were heading out around 2pm. All on E/S aspects near rocks or cliffs. Most were relatively small and had not entrained much snow from the surface or gouged deeper than a few inches.

On the drive back to town, we noted 5 or so larger wet loose avalanches in Argentina Bowl, with a good number of smaller slides at different points along the ridge

Seeing as it is now the season for wet snow hazards, there are a few things that are critical to consider: aspect, elevation, and timing.

Timing your day to be off of steep slopes before melt water percolates too deep and destabilizes the slope is key, AND making sure to account for steep low-elevation slopes that you may have to pass through on your way back to the trailhead. If you start to sink in deeper than your ankles, or your sled track is digging into slush, that means it is time to either shift to colder aspects or head back to the trailhead.

Our greatest concern with these wet loose avalanches is not so much their size, but their power to push you into terrain traps like cliffs, gullies, trees, or rocks. The two scenarios when we are most concerned about these avalanches are when new snow gets wet and sheds for the first time OR when there have been multiple days without a solid refreeze and melt-water percolates deep into the snowpack.

Number caught

Number buried

Avalanche Type

Wet loose-snow avalanche

Trigger

Natural trigger

R size

D size

Bed Surface

I - Interface between new and old snow

Problem Type

Wet Snow