Natural avalanche that occurred at Bridger early on 5/9/22. There were many similar depth natural crowns along the ridge that broke within the recent snow that fell over the weekend.
Trip Planning for Island Park
Bottom Line: Spring weather can be highly variable and create a mix of avalanche problems to watch out for. Snow conditions and snow stability can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Plenty of snowfall over the winter with more spring snow to come makes avalanches possible into summer.
Primary Problem: None
Snow Observations- Island Park & Lionhead
Island Park
Sawtelle Peak
Explaining Wet, Isothermal Snow
I dug a pit at 9,300' on a SW facing slope close to the Sawtelle Road. The snow was wet and has lost a lot of strength. I was breaking through a 2" frozen crust at the surface into wet, mushy snow. Once the crust breaks down I expect wet avalanches to continue. The snowpack is 6' deep, very thin for this time of year. Water was able to penetrate this depth quickly. Be careful traveling later in the day when the crust begins to melt and you sink far. This is a sign of instability.
Full Snow Observation ReportIsland Park
Tin Cup Pass
Stability just got worse
We rode a loop of Yale Ck, to MT Jefferson, to Hellroaring Ck, to Tin Can Pass, then a beeline back to IP. There was maybe 4+” of new snow which made all the difference in riding quality. There were no avalanches and no wind. Skies were blue and temp stayed below freezing. We dug at the same pit at Tin Cup Pass I did 2 previous times, but this time we got propagation in an ECT13 on the SH buried 30 cm deep. The other two times we did not. With the weak layer getting ECTPs I’m thinking with snow we should see even more avalanches. But it all might get wet from warm temperatures before then.
Full Snow Observation ReportIsland Park
Sawtelle Peak
Good stability around Sawtelle Peak
We dug around checking on snow stability for tomorrows KLIM Frozen Cow Tag event. There is only a couple inches of new snow and no wind. We saw no avalanches or signs of instability and our 2 snowpits were stable.
Full Snow Observation ReportIsland Park
Mt Jefferson Bowl
Good stability around Mt Jefferson and Reas Peak
We had warm temps and good visibility as we rode into Yale Creek. We saw no avalanches, just a lot of wind affected terrain. We rode out and back: Yale Creek, Mt. Jefferson Bowl, Hellroaring Creek past Reas Peak and dug a pit at Tin Cup Pass. Once we got into Hell Roaring Creek we could find soft snow that was just old snow that faceted. We dug at Tin Cup Pass on a NE facing slope at 8,000'. It was the same spot I dug on February 6 and the hole was plainly visible. We dug to the ground (HS 175) and found a stable snowpack (ECTX). The snow structure: weak facets at the ground, then Pencil to Knife hardness slab, then weak, very sugary snow in the top 18” (plus the 2 surface hoar layers). As I walked over from the sleds to the wind-loaded cornice edge I got a whumph but did not see a crack. It was a wind slab on facets that broke. Very isolated but it reminded me of the Lionhead fatality. Small, wind-loaded terrain. Danger felt generally stable, but the whumph was real and made me wonder what other small terrain features are harboring this instability. Basically, be wary around wind slabs!
Full Snow Observation Report
Island Park
Sawtelle Peak
Sawtelle Peak - Centennials
We dug two pits near where Doug and Ian were on January 12th. There has been so little snow since then that one of their pit sites was still clearly visible 6-7 weeks later. We could use some snow! The story here is very similar to that in the ranges from West Yellowstone through Big Sky. The top foot of the snowpack is very weak and getting weaker but we are waiting for snow before anything outside of isolated areas becomes unstable. ECTXs in both pits. The lower snowpack is largely locked up for now with a thick layer of pencil hard snow (rounds) below the facets.
The total snow depth is ~200 cm which is less than what Doug and Ian found over a month ago.
Bottom line: Stable for now, but this will change dramatically with a decent snowstorm.
Full Snow Observation ReportIsland Park
Yale Creek
Stamp Meadows/Sawtell Area
We parked at Sawtell Parking area on Friday. We rode into Whit Elephant Canyon, Tyler Creek, and the ridge between Stamp Meadows Trail and Yale Creek. We dug 2-3' a west facing pit in White Elephant Canyon at 6,000 ft. elevation 50/50 open area with some shading. This pit was solid consolidated snow to the dirt and not any noticeable solar affect, and no faceted snow at the ground. We got no results on the ECT and had to pry the block out. On the Tyler Creek pit again 2-3' we were at 6,500 on a north facing slope in heavy tree cover. At ground level we had 3 to 4" of faceted snow. It we extremely obvious. This pit we got initiation, in the 25 hit area, no ECTP. The thing that stood out for us as I was teaching a new IDPR Educator was the significant difference at ground level with the faceting snow, just in the change of aspect. For the ridge pit above Sawtell Road we were at 7,100 ft., on a south east open facing slope around 3.5'. We had about 1cm to 1.5cm think solar crust developing. You could only hold about a 10" pie pc together before it broke. Not much strength in the solar crust. Under that pretty consolidated snow and minimal faceting at ground level. This pit also initiated at 25 hits but no ECTP results.
We took our class on Saturday to the Tyler Creek pit since it had layering with that 3-4" of faceted snow. Again we manipulated this pit as hard as we could to try and get propagation by tricks Dave Zinn had showed me but we could not get past just initiation.
Full Snow Observation Report
Island Park
Yale Creek
Hotel/Yale Creek
Wednesday we were on snowbikes in the Hotel/Yale Creek drainages. We beat the snow up pretty hard on steep short slopes with no signs of instability. There was approximately 1" to 1.5" of new snow within the last week that could have easily been surface frost, frozen fog or just light snow. The weather was mild with clear skies to partly cloudy skies and a minimal amount of new snow falling. There is about 3 layers in the snow pack, the surface was light for the top 1/3, getting ice and crusty on the south slopes. We could hear the ice on the skies. The middle third of the snow pack is pretty consolidated, and the bottom snow pack with the temperature variance with the last weeks of high pressure systems seems to be falling apart and faceting. What we have seen in the last couple of weeks is a pretty solid base, however, with the longer high pressure systems, it appears to be coming apart down low towards the ground. We have seen this in many places in Eastern Idaho lately. Many of the streams are open in the big drainages due to the lack of snow. Places to cross can be challenging.
Full Snow Observation ReportIsland Park
Tin Cup Pass
Good stability outside Island Park
From the Gallatin NF Avalanche Center:
We rode up Yale Creek, then to the Mt. Jefferson Bowl, then to Tin Cup Pass north of Mt Raes. We saw no avalanche activity or signs of instability. It was calm out and the wind was not moving snow. The debris piles on Mt. Jefferson were from an avalanche cycle the end of December and they are still visible. January has been dry!
Our stability test did not break on the surface hoar. There needs to be more snow on top of it. Possibly on a wind drifted area, but in general, the stability is good until we get more snow.
Full Snow Observation Report
Island Park
Reas Peak
Thin and stable conditions
Just wanted to update you on what we found yesterday in the field working on the Frozen Tag.
We rode on the south side of Sawtelle Road below Rae’s Peak and Stamp Meadows Trail and no surprise to anyone we did not find much snow. What snow was there was hero snow with about a foot of loose dry snow on top of a pretty solid base. We did not see or find any signs of instability where we were at. We beat the snow up pretty hard on convex rolls, small wind loads, and short steep slopes with no results.
The biggest concern we found was open streams. A lot of the drainages have few snow bridges in them. But that was really about it.
Full Snow Observation ReportIsland Park
Centennials - Idaho
Stable test Island park
location
44°30'31.0"N 111°33'29.0"W
WSW aspect
7413'
depth 77cm
ECTX
PST 95/100 @15cm
Full Snow Observation Report
Relevant Avalanche Activity
Bridger Range
Bridger Bowl
Many natural storm snow slab avalanches at Bridger
Bridger Bowl
SS-N-R2-D1.5-S
Elevation: 7,500
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0
More Avalanche Details
SS-N-R2-D1.5-S
Elevation: 7,500
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0
There were many similar depth, 8-12" natural crowns along the ridge that broke this morning or overnight within the recent snow that fell over the weekend.
More Avalanche Details
Relevant Photos
Displaying 1 - 40
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Crown of a natural avalanche that occurred at Bridger on 5/9/22. There were many similar depth natural crowns along the ridge that broke within the recent snow that fell over the weekend.
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Natural wet loose avalanche in Beehive Basin. Occurred on Wednesday 5/4 after new snow fell on Tuesday.
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Wet loose snow avalanches of recent 6" of snow. They likely occurred when the sun came out Wednesday morning, or at the end of the storm on Tuesday. GNFAC
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"5/3/22 at approximately 4:00pm a storm slab avalanche occurred in beehive basin on a west aspect @9000 ft. This slab was 6-8” deep and propagated around 50’. No one was buried, however we aren’t sure if anyone was caught because we were not the party who triggered this avalanche. We did witness the party drop in but quick went out of sight." Photo: H. Bigos-Lowe
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On 4/18/22 near Cooke City we witnessed natural rollerballs and pinwheels by 11 am, and a couple wet loose slides below cliffs on southerly slopes around noon, and were able to easily trigger pinwheels on west-southwest aspects around 1230-1pm. Photo: GNFAC
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A large drift on the Ramp just north of Bridger Bowl. Photo: GNFAC
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Drifts cracked and slid on steep rollovers north of Bridger Bowl. Photo: K Hammonds
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An avalanche on Wilson Peak that caught two skiers and injured one on 4/3/22. Photo: GNFAC
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On 3/27/22 Big Sky ski patrol witnessed many natural wet slides in closed terrain. Photo: BSSP
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"We also conducted avalanche mitigation on our Cabin’s Road at 4:30pm. The snowpack in this zone doesn’t get skied and is representative of the backcountry. The slope is ENE around 8,400’. Several wet slab avalanches were produced with explosives and ski cutting. The avalanches ranged from R4/D2 to R2/D1. They all hit the road and several crossed, and buried, the Cabin’s Road. Although most of this mitigation was done with explosives, it took minimal effort with skis to get snow moving. The crowns were 2-3’ deep and ran on the ground." Photo: YCSP
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"A wet loose avalanche was seen in the Apron (closed terrain that hasn’t been opened this season) around 3:00pm. It was an R2/D2 on a east facing slope around an elevation of 8,500’." Photo: YCSP
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Natural wet slab avalanche on Cedar Mtn. Observed 3/26/22. Photo: J. Gerardi
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From obs 3/26/22: "Freezing temps overnight created breakable crust in the morning which quickly deteriorated as the day warmed. (Temps rose surprisingly faster than we anticipated. Experience large whumphs while ascending the NW shoulder of Electric Pk. at 9600 ft. Without hesitation we turned back and skied out the skin track. The snow became very rotten and we penetrated to boot-tops often while exiting." Photo: S. Miller
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On March 26 many natural wet slides occurred in closed terrain at Bridger Bowl. Photo: BBSP
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We saw this natural avalanche on 3/19/22 appeared to be within 24 hours old and triggered by cornice fall that broke out a slab below. Northeast aspect at 8,800' on Lionhead Ridge. Photo: GNFAC
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We saw this natural avalanche on 3/19/22 appeared to be within 24 hours old and triggered by cornice fall that broke out a slab below. Northeast aspect at 8,800' on Lionhead Ridge. Photo: GNFAC
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We saw this natural avalanche on 3/19/22 appeared 24-48 hours old and triggered by cornice fall that broke out a slab below. North aspect at 10,000' behind the top of Targhee Creek near Lionhead. Photo: GNFAC
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At Lionhead, east wind was blowing up the normal starting zones and moving snow. Once it switches westerly the wind loads will create instability. There is 10-12" of powdery snow to blow around. Photo: GNFAC
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Wet slides occurred near Quake Lake on 3/3 or 3/4. Photo. T. Hansen
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Doug Chabot performing an ECT in a 6 foot deep, generally stable snowpack near Tincup Pass in the Centennial Mountains (outside Island Park). 3/2/22. Photo: GNFAC
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We dug a pit at 9,000' on an east facing slope on Sawtelle Peak on 2/24/22. Our old pit from 1/12/22, almost 6 weeks ago, is still plainly visible in the foreground. It has been a dry 6 weeks! Photo: GNFAC
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From message 2/20/22: "Triggered this slide yesterday a few miles from two top. 1.5 foot crown."
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From message 2/20/22: "Triggered this slide yesterday a few miles from two top. 1.5 foot crown."
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This is the slope that avalanched and killed a snow bike rider (motorized) on 2/19/22. Photo is from the Search and Rescue team who were leaving the site as it was getting dark, and did not have time to gather more info. Click link below for more details. Photo: B. Zavora
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We saw this fairly recent, very small cornice fall avalanche on Cedar Mtn. on 2/12/2022. Photo: GNFAC
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Chris Hericks, snow ranger on Beaverhead Deerlodge NF, points to the lower of two surface hoar layers. We are finding similar layering throughout our entire forecast area. The top 18" of the snowpack is weak and will quickly become unstable when it snows. Photo: GNFAC
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The crown is not visible (it is down and right) but the X marks the approximate spot the rider was found. Photo: GNFAC
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The crown was measured 4-11 inches deep and 75 feet wide. Photo: GNFAC
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Looking at a weak layer of facets that the avalanche propagated on. Photo: GNFAC
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Looking at the crown from below. Photo: GNFAC
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On Sunday, February 6, Gallatin Country Sheriff Search and Rescue and the GNFAC responded to a avalanche in Lionhead. A snowmobiler was killed on a small steep slope when a shallow avalanche carried him into a terrain trap of trees. Photo: GNFAC
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This morning while ascending a line on Sawtooth Mountain (Lower Novocain) we triggered an avalanche (ASu-SS-R2-D2-O) that caught and carried my partner an estimated 180M and partially buried him. His leg and hand were unburied and excavation of the head was done in less than 2 minutes of the incident. The avalanche only involved new snow from the last 48hrs and was triggered on a MF crust/facet combo 30cm down(formed 1/30/22). The avalanche was 30cm at its deepest and 20-30M wide and ran 250M. We were lucky to find both skis and poles a little ways downslope. No injuries were sustained.
We both agree that we were trying to outsmart the instability that was present on steeper S facing terrain and should have turned around much sooner, we were very lucky. There was 30+cm HST in favored areas and the high winds from 1/31/22 formed some sensitive windslabs in specific areas.
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Graph of Snow Water Equivalent (SWE) at SNOTEL sites in the GNFAC forecast area from October 1, 2021 to January 30, 2022. It highlights the extended dry conditions in January that contributed to weak layers forming at the top of the snowpack. GNFAC
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We rode at Lionhead today (Jan. 29, 2022) and found very weak snow on the surface which is not a problem now, but will be when we get more snow. Photo: GNFAC
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Riders reported on 1/15/22: "Some surface hoar is forming on nearly every aspect at all elevations. over 1 cm thick in some areas." Photo: B. Rasmussen
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Riders reported on 1/15/22: "Some surface hoar is forming on nearly every aspect at all elevations. over 1 cm thick in some areas." Photo: B. Rasmussen
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Settlement rings around the base of trees near Cooke City, January 15, 2022. Photo: B. Fredlund
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Ian Hoyer stands in the 7 foot deep snowpit we dug to look at layering and stability. Stability was good. We dug at 9300' off the Sawtelle Peak Road to keep tabs on stability since we put out warnings and basic information for this area on our Trip Planning page. Photo: GNFAC
Videos- Island Park & Lionhead
Weather Forecast- Island Park
Extended Forecast for
10 Miles ESE Lakeview MT
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Overnight
Chance
Rain/SnowLow: 34 °F
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Sunday
Rain/Snow
High: 39 °F
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Sunday
NightRain/Snow
then SnowLow: 32 °F
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Memorial
DayRain/Snow
then ShowersHigh: 40 °F
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Monday
NightRain/Snow
Likely then
Chance SnowLow: 31 °F
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Tuesday
Chance
Rain/Snow
then Chance
ShowersHigh: 47 °F
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Tuesday
NightSlight Chance
Rain/Snow
then Partly
CloudyLow: 30 °F
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Wednesday
Mostly Sunny
then Chance
ShowersHigh: 52 °F
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Wednesday
Night
Partly Cloudy
Low: 34 °F
The Last Word
Thank you to everyone that sent in observations, read the advisories, took an avalanche class or donated money, time or gear. Our success is directly related to community support and the Forest Service. Have a safe spring and summer! See this article for some general spring travel advice.