Trip Planning for Southern Madison

Snowmobile triggered avalanche likely on Saturday, Feb 22. It appeared that no one was caught or buried.

Snowmobile triggered avalanche that resulted in a partial burial with no injuries on Friday, Feb 21.

Snowmobile triggered avalanche that resulted in a partial burial with no injuries on Friday, Feb 21.

From IG message: "We remotely triggered this hillside in Taylor's fork yesterday [2/21] from the Ridgeline above it. We were looking for a safe spot to drop down when it released below us. Circled around for some pictures. The snow was pretty shallow, only 2-3 feet deep, and slid to the ground. South facing slope"

From IG message: "We remotely triggered this hillside in Taylor's fork yesterday [2/21] from the Ridgeline above it. We were looking for a safe spot to drop down when it released below us. Circled around for some pictures. The snow was pretty shallow, only 2-3 feet deep, and slid to the ground. South facing slope"

From IG message: "We remotely triggered this hillside in Taylor's fork yesterday [2/21] from the Ridgeline above it. We were looking for a safe spot to drop down when it released below us. Circled around for some pictures. The snow was pretty shallow, only 2-3 feet deep, and slid to the ground. South facing slope"

 There was a thin melt/freeze crust formed on solar aspects lower down (up to ~500 feet above the parking). Photo: BP

From email: "One of my crew was partially buried in an avalanche today(head about 1’ down, leg and arm still above snow) at approximately 13:10 hrs.  Slope was greater than 35 degrees, crown approximately 85 yards wide, over 3’ at its thickest point.  I believe it was a NE exposure with wind loading at the top.  I had a bad feeling about this slope and mentioned it to my crew and avoided riding on it until one rider ran out of gas and I had to help him.  Upon completion of task, I rode back to a spot that wasn’t as safe a vantage point as what I had previously stayed at, but the intention was we were all on our way out.  So I parked and within 30 seconds, I hear my friend yelling behind me. I turn and immediately think “oh he’s about to hit us”.  So, I  attempted to start up my sled, to no avail While watching behind me.  Suddenly, a massive “snow cloud” appeared about 30 yards above him and it took about 2-4 seconds to register that it was an avalanche and not another rider careening out of control at us.  By that time, it was too late to do anything.  The avalanche had reached the back of my friend and my sled, pushing us forward about 6 feet at 3-4mph.  After it stopped, I assessed 3 of four of our team was accounted for, and one (the one who yelled at us) was not.  He was partially buried by the front of the avalanche much like our sleds were.  Fortunately, within 5 seconds, I saw an arm and a leg sticking out of the snow and we had his airway and head cleared within about 20 seconds.   He was located approximately 10 yards from us.  "

From email: "One of my crew was partially buried in an avalanche today(head about 1’ down, leg and arm still above snow) at approximately 13:10 hrs.  Slope was greater than 35 degrees, crown approximately 85 yards wide, over 3’ at its thickest point.  I believe it was a NE exposure with wind loading at the top.  I had a bad feeling about this slope and mentioned it to my crew and avoided riding on it until one rider ran out of gas and I had to help him.  Upon completion of task, I rode back to a spot that wasn’t as safe a vantage point as what I had previously stayed at, but the intention was we were all on our way out.  So I parked and within 30 seconds, I hear my friend yelling behind me. I turn and immediately think “oh he’s about to hit us”.  So, I  attempted to start up my sled, to no avail While watching behind me.  Suddenly, a massive “snow cloud” appeared about 30 yards above him and it took about 2-4 seconds to register that it was an avalanche and not another rider careening out of control at us.  By that time, it was too late to do anything.  The avalanche had reached the back of my friend and my sled, pushing us forward about 6 feet at 3-4mph.  After it stopped, I assessed 3 of four of our team was accounted for, and one (the one who yelled at us) was not.  He was partially buried by the front of the avalanche much like our sleds were.  Fortunately, within 5 seconds, I saw an arm and a leg sticking out of the snow and we had his airway and head cleared within about 20 seconds.   He was located approximately 10 yards from us.  "

Snowmobile triggered avalanche in Teepee Basin. 

Large cornice fall triggered avalanche in Sage Creek, Photo: GNFAC

This snowpit on a SE aspect was made up of a dense slab of recent snow, sitting on top of many different layers of junky, faceted grains. Propagation was easy to find (ECTP 11, HS: 112).  Photo: GNFAC

We saw up to five recent avalanches from the last few days. 1-2 looked to have failed on PWLs, and the rest were wind slabs. Cornice collapses triggered at least two of these avalanches. Photo: GNFAC

Taylor Fork, Feb 13. Photo: GNFAC

We rode into the Taylor Fork on Feb 13, down into the bottom of Sunlight Basin, across Carrot Basin and to the Wilderness Boundary. We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Additionally, we saw one wind slab avalanche (R1, D1) in Sunlight Basin. This slide was fresh from this morning or yesterday. Photo: GNFAC

We rode into the Taylor Fork on Feb 13, We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Photo: GNFAC

We rode into the Taylor Fork on Feb 13, We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Photo: GNFAC

Buried layers of surface hoar often show up a stripe in a snowpit wall (other things such a thin melt-freeze crust can look similar but feel much differently). A snowmobiler-triggered avalanche in Sunlight Basin broke on this weak layer of feathery surface hoar. Photo: GNFAC

Relatively small persistent slab avalanche in Carrot Basin in the Taylor Fork. Photo: GNFAC

We rode into the Taylor Fork on Feb 13, We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Photo: GNFAC

Persistent slab avalanche on a wind loaded slope in Sage Basin in the Taylor Fork area. Photo: GNFAC

Alex Marienthal walks up the bed surface of an avalanche to investigate the snowpack structure. Photo: GNFAC

Shooting cracks in a drift in the Taylor Fork. Photo: GNFAC

From FB message: "Two snowmobiler triggered avalanches in Southern Madison. Riders did not have beacons or rescue equipment. Riders made it out safe luckily."

From FB message: "Two snowmobiler triggered avalanches in Gravelly Range. Riders did not have beacons or rescue equipment. Riders made it out safe luckily."

Alex documenting the stratigraphy on a W aspect at 8850' near the Wilderness Boundary

On a north aspect at 9200 ft, there were 1mm facets chained together almost 10mm long.

A layer of nsf's and surface hoar was failing ~10 inches deep producing easy ECTP's

A layer of nsf's and surface hoar was failing ~10 inches deep and causing shooting cracks

A layer of nsf's and surface hoar was failing ~10 inches deep and causing shooting cracks

A layer of nsf's and surface hoar was failing ~10 inches deep and causing shooting cracks

Buried SH below the 2/1 storm. 1-2cm thick layer buried approximately 20cm deep below F precip particles. Photo: M Zia 

From email: "Today I drove down Taylor fork road, with the thought of potentially getting up on woodward mtn, until I saw a crown on the NE
Face of its northern summit, basically wall to wall near the top of  the slide path. There were a couple other sled tracks that also went to the end of the road, so I figured maybe it was pretty recent, as I didn’t hear about it in the advisory. Concerning because it appears to have propagated maybe 250ft across,  while maybe only 1-2 ft deep". Photo taken on 1/30/25. Photo: T. Grande

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked..." C. Fregian

Screenshots from videos sent in messenger

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked..." C. Fregian

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked..." C. Fregian

Screenshots from videos sent in messenger

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked…"

Screenshots from videos sent in messenger

From FB message 1/19: "In between redstreak peak and white peak... The whole slope cracked...”

Screenshots from videos sent in messenger

Natural avalanche spotted from the air on Red Mountain, just west of Ernest Miller Ridge

USFS Snow rangers commuting to and from West Yellowstone noticed a human-triggered avalanche across the Gallatin River from Bacon Rind. Photo: K. Marvinney