Regional Conditions for Northern Madison

A snowmobiler triggered this small avalanche on Friday (1/11) between the 3rd Yellow Mule and McAtee Basin on Buck Ridge. The slope has a terrain trap at the bottom where snow can pile deep and makes small slides more dangerous. The relatively shallow snowpack is weaker and shows that a poor snowpack structure exists on some slopes in the northern mountains of our advisory area, and makes avalanches possible to trigger. Photo: GNFAC

This graph shows snow water equivalent (SWE) by date at the primary SNOTEL sites that we use in the GNFAC region. From October 1st, 2018 to January 12th, 2019. Steeper lines indicate bigger storms and flatter lines indicate periods of little to no snow. A large storm at the beginning of Novermber laid down a 1-3 foot base. Relatively dry and cold weather through November caused much of that snow to become weak. This weak snow was buried by a series of storms. Avalanches were seen during and following many of these storms. During dry weather between storms, more weak layers formed on the surface of the snowpack and were subsequently buried. (Graph created by GNFAC from NRCS provisional data).

February 2, King and Queen of the Ridge at Bridger Bowl (fundraiser). Register with Bridger to hike in the event, and create a pledge page to raise funds with your Ridge laps.

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure.

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure. 

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure. Photo: GNFAC

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure. Photo: GNFAC

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure. Photo: GNFAC

From e-mail: "...in bhive today, as I rolled into a W facing gully  at around 9800ft I got a good whumph, I noticed a 25ft wide crack probably about 8 inches deep, it did not run just fractured.  I checked it out seemed like it broke on an older slab sitting on that facet layer from early December." Photo: T. Grande

Skiers on Wilson Peak observed "widespread whoomfing and could visibly see the slopes drop/collapse on the climb through the trees". They dug a pit and found facets buried 40 cm deep and unstable test results at ECTP23. Photo: J. Die

A snowmobiler triggered this slide in the 3rd Yellowmule of Buck Ridge on Monday (12/31). It was an east facing slope. Photo: K. Crisman

Skiers observed many natural avalanches in Beehive Basin yesterday (12/31). "My partner counted 12+ including this one... All avalanche activity was on E or NE slopes which had been hammered by the winds." Photo: M. Cohen

From the Yellowstone Club Ski Patrol, " ...we noted 2 natural avalanches along one of our roads. They both are at about 7000ft and had a relatively shallow snowpack. The crowns were roughly 2ft in depth and ran on facets near the ground. One slide looks like it released during the yesterday’s storm and the other appears to have gone either overnight or this morning." Photo: YCSP

From the Yellowstone Club Ski Patrol, " ...we noted 2 natural avalanches along one of our roads. They both are at about 7000ft and had a relatively shallow snowpack. The crowns were roughly 2ft in depth and ran on facets near the ground. One slide looks like it released during the yesterday’s storm and the other appears to have gone either overnight or this morning." Photo: YCSP

From an email, " Patrollers also spotted a natural avalanche outside of the ski area boundary in the Eglise Bowl. The photo was taken from a distance but the aspect is NE and the elevation is around 8500ft. " Photo: YCSP

Snow bikers in the northern Gallatin Range "witnessed a very reactive new snow layer in all wind loaded areas." (12/30). Photo: J. Polus

Snow bikers in the northern Gallatin Range found unstable test results on the early December facet layer (12/30). "While snow biking... We dug a snow pit at 9100 ft elevation & discovered a weak layer that propagated at 28 on the ECT test about 18 inches down. The snow below that area was all loosely faceted." Photo: J. Polus

We rode into the 2nd Yellowmule of Buck Ridge and found 2 instabilities: new snow, and facets that formed in early December. The facets are buried 1.5' under the surface and broke with an ECTP24. Two weeks ago we dug in the same spot and got ECTP10. Things are slowly getting stronger, but this weekend's snowstorm may be enough to break it and avalanche. Photo: GNFAC

From e-mail on 12/23: "About an 8 inch slab triggered by snowmobilers. South facing slope in the 3rd yellowmule at buck ridge." Photo: Crisman

This wind-loaded pocket was triggered in the 2nd Yellowmule of Buck Ridge on 12/22. Photo: M. Alvarez

Ski patrol triggered this avalanche at the Yellowstone Club on Sunday (12/16). "R3/D2 (8400’, ENE facing, 36deg start zone) that was about 120’ wide and ran vertically 200’. The crown was 1.5-2’, went to ground, and was a mostly faceted snowpack with a bit of wind effected snow in the top few inches. The slide was released from a 4lb air blast." Photo: YCSP

Ski patrol triggered this avalanche at the Yellowstone Club on Sunday (12/16). "R3/D2 (8400’, ENE facing, 36deg start zone) that was about 120’ wide and ran vertically 200’. The crown was 1.5-2’, went to ground, and was a mostly faceted snowpack with a bit of wind effected snow in the top few inches. The slide was released from a 4lb air blast." Photo: YCSP

A snowmobiler triggered this avalanche on Saturday (12/15) near Buck Ridge. It is on a wind loaded slope and likely broke on buried facets that formed in early December.

This wind-loaded slope was triggered Sunday morning (12/16) by a snowmobiler. The debris was hard slabs of wind-drifted snow. The avalanche broke on a layer of small sized facets that formed during the frigid, clear weather 10 days ago. No one was caught. Photo: GNFAC

This wind-loaded slope was triggered Sunday morning (12/16) by a snowmobiler. The debris was hard slabs of wind-drifted snow. The avalanche broke on a layer of small sized facets that formed during the frigid, clear weather 10 days ago. No one was caught. Photo: GNFAC

Our snowpit showed instability in the small, sugary facets that are underneath a hard slab of wind blown snow. An avalanche was triggered around the corner from this snowpit around the same time we were digging! Photo: GNFAC

These natural slides are on a heavily wind loaded slopes, and were observed on Saturday (12/15). Debris ran into the trees at the bottom of the bowl. Photo: @dinsmoredigital

These natural slides are on a heavily wind loaded slopes, and were observed on Saturday (12/15). Debris ran into the trees at the bottom of the bowl. Photo: @dinsmoredigital

Crack in a drift that collapsed 30 feet wide, accompanied by an audible "whumph", as we skinned over it. 12/15/18 West side of Bridger Range. Recent strong winds formed hard slabs over weak surface hoar and facets. Photo: GNFAC

Big Sky Ski Patrol saw two natural wind slab avalanches during control this morning that had released after being loaded by strong winds last night. From BSSP: "We observed the evidence of 2 small naturals this am in the upper cirque where the strong winds had managed to deposit some snow very low below cliff bands. We did not see this loading pattern anywhere else on the hill." Photo: BSSP

Photo: @msubackcountryclub

Wind loads were easy to trigger. This one was triggered on purpose up Maid of the Mist in Hyalite. Photo: A. Peterson

Wind slabs were easily triggered. Although small in size, they indicate that larger slopes would have larger avalanches. Photo: A. Peterson

From some skiers: "We encountered veey localized loading that easily fractured and propagated uphill on a south aspect." Photo: S. Reinsel

From some skiers: "We encountered veey localized loading that easily fractured and propagated uphill on a south aspect." Photo: S. Reinsel

Skiers triggered these loose snow avalanches on Sunday (12/2) on a west-southwest aspect in Beehive Basin. Photo: T. Allen

From e-mail: "triggered a small wet slide in the Going Home chute coming back into Beehive, and we observed another natural wet slide on a similar aspect that had occurred since we toured past in the morning. Wind was light or calm all day and wind effect was minimal even at ridgelines." Photo: C. Kussmaul

From e-mail: "triggered a small wet slide in the Going Home chute coming back into Beehive, and we observed another natural wet slide on a similar aspect that had occurred since we toured past in the morning. Wind was light or calm all day and wind effect was minimal even at ridgelines." Photo: C. Kussmaul

Skiers in Beehive on Sunday (12/2) reported lots of previous natural point releases. Photo: H. Copolillo

We observed this wind slab and debris on Sunday (12/2). It likely formed from the new snow and wind on Saturday morning. Photo: GNFAC