Regional Conditions for Northern Madison

Outside Cooke City up Zimmer Creek, a skier spotted this cornice fall which triggered a small pocket down low. Photo: F. Madsen

Many wet loose and wet slab avalanches were seen near Zimmer Creek (north of Cooke City) on south and east aspects. Temperatures were warm at 10,000 feet. Photo: F. Madsen

Wet slab avalanches will be a growing concern as free moving water travels through the snowpack. This problem is most likely on mid to low elevation slopes that have a shallow snowpack and poor structure. Be aware of wet slabs as temperatures warm and the snowpack becomes increasingly unstable. Photo: GNFAC 

Warm temperatures are causing large cornices to lose strength. Be cautious when traveling on slopes below cornices and give them a wide berth along near ridgelines. Photo: GNFAC 

Above freezing temps and direct sunshine are creating unstable conditions on steep sun-exposed slopes. This problem is most common in steep rocky terrain or areas with a shallow and weak snowpack. Move to shadier aspects or away from steep terrain if point releases are occurring. Photo: GNFAC 

This photo near Lionhead, is indicative of the wet loose avalanches we are seeing on many low elevation, south facing slopes throughout our advisory area. Daytime temperatures near 50F will make avalanches like this more frequent and widespread in the coming days.

Slab avalanche that broke on Fan Mountain near Big Sky on 3/15/2019. Photo taken on 3/18/2019. Photo: J. Hageness.

This avalanche ran on Friday (3/15) near Big Sky. It was probably triggered by a cornice fall during warm temperatures late in the day. Photo: E. Howard

Low angle metal roofs have heavy, thick slabs of snow that built up during persistent cold temperatures. These slabs will slide during warm temperatures. Be on the lookout for overhead hazard and be cautious where you walk or park your car during warm sunny days. An additional urban hazard are large icicles are that will break during warm days. Photo: A. Schauer

"A few small wet loose releases were observed in areas without skier traffic but were confined to the top couple of inches on top of our previous high pressure surface.  The attached pic is the largest of those wet loose results and was a size 1 in Buffer Chute, in the Upper A-Z’s and occurred after that terrain had closed for the day." Photo: BSSP

On Friday (3/15) dry loose avalanches were easily triggered on steep terrain in Hyalite. Six inches of recent snow easily slid on crusts buried below it, and was drifted into small wind slabs near ridgelines. These types of small slides are typically not large enough to bury a person, but are dangerous if they catch and carry you over cliffs or into trees. Photo: GNFAC

A skier reported watching a group trigger this windslab near Beehive Peak. Slab was 6-8" thick, 100' wide, and ran for around 600'. Luckily, nobody was caught or buried. This photo was taken near the toe of the debris pile.

A skier reported watching a group trigger this windslab near Beehive Peak. Slab was 6-8" thick, 100' wide, and ran for around 600'. Luckily, nobody was caught or buried. Skiers are circled in the bottom left of the frame for scale.

On southwest facing slopes in Beehive there was a layer of well developed facets under the melt freeze crust at the surface. If the weather forecast holds true, sunny skies and above freezing temperatures will destroy these. If they get buried deeply they could be a future problem. Photo: GNFAC

This deep slab avalanche appeared to have been triggered by skiers on Saturday (3/9) or Sunday (3/10). It shows the type of terrain to avoid in order to avoid triggering a big avalanche: Variable snow depth, complex and rocky. Photo: D. Sandberg

This deep slab avalanche appeared to have been triggered by skiers on Saturday (3/9) or Sunday (3/10). It shows the type of terrain to avoid in order to avoid triggering a big avalanche: Variable snow depth, complex and rocky. Photo: D. Sandberg

This deep slab avalanche appeared to have been triggered by skiers on Saturday (3/9) or Sunday (3/10). It shows the type of terrain to avoid in order to avoid triggering a big avalanche: Variable snow depth, complex and rocky. Photo: T. Grande

This deep slab avalanche appeared to have been triggered by skiers on Saturday (3/9) or Sunday (3/10). It shows the type of terrain to avoid in order to avoid triggering a big avalanche: Variable snow depth, complex and rocky. Photo: T. Grande

On Saturday (3/9) skiers observed multiple large natural avalanche crowns near Wilson Peak and Dudley creek in the northern Madison Range. They appeared to break on weak layers near the bottom of the snowpack. Photo: G. Egnew

On Saturday (3/9) skiers observed multiple large natural avalanche crowns near Wilson Peak and Dudley creek in the northern Madison Range. They appeared to break on weak layers near the bottom of the snowpack. Photo: A. Pohl

On Saturday (3/9) skiers observed multiple large natural avalanche crowns near Wilson Peak and Dudley creek in the northern Madison Range. They appeared to break on weak layers near the bottom of the snowpack. Photo: A. Pohl

On Saturday (3/9) skiers observed multiple large natural avalanche crowns near Wilson Peak and Dudley creek in the northern Madison Range. They appeared to break on weak layers near the bottom of the snowpack. Photo: A. Pohl

A snowmobiler saw this recent activity on Saturday 3/9/19 on Cedar Mountain near Big Sky.

This slide was triggered on a steep (40 deg) southeast facing slope at Round Lake outside Cooke City. It failed 8" deep on a layer of graupel and small facets. An adjacent hill slid at the same depth beforehand. This layer is not on most slopes, but as this slide shows it is on some. Doug was in the area and dug a pit in the crown soon after it was triggered. Photo: J. Fritz

This slide on the NE face of Blackmore was triggered by the second skier. It was 8-12" deep and 100' wide and likely failed on small faceted crystals underneath the new snow. No one was caught. Going one at a time was good travel behavior that can save our lives when things go wrong.

"The YC Ski Patrol conducted avalanche mitigation work above another one of our roads today. The area is outside of our ski area boundary and receives no skier traffic. A 4lb explosives charge was detonated from an aerial tram and triggered a R2/D2 avalanche that ran to the ground. The crown was 2', the path width was around 100', and it ran 350 vertical feet (crossing the road) to the bottom of the runout zone. The elevation was 7280' on a NNW aspect and max slope angle of 34 degrees. Other sections of this slope were tested with explosive charges, yielding only black holes." Photos and observation courtesy YC Ski Patrol.

"The YC Ski Patrol conducted avalanche mitigation work above another one of our roads today. The area is outside of our ski area boundary and receives no skier traffic. A 4lb explosives charge was detonated from an aerial tram and triggered a R2/D2 avalanche that ran to the ground. The crown was 2', the path width was around 100', and it ran 350 vertical feet (crossing the road) to the bottom of the runout zone. The elevation was 7280' on a NNW aspect and max slope angle of 34 degrees. Other sections of this slope were tested with explosive charges, yielding only black holes." Photos and observation courtesy YC Ski Patrol.

Multiple natural avalanches released on Fan Mountain in the past few days. Some of the smaller slides were confined to the new snow, while two larger slides broke on deep persistent weak layers an ran a long distance. Photo: M. Delguidice

Snowmobile-triggered avalanche near Cedar Mountain. Photo: YCSP

Deepest part of crown from slide triggered 3/2 by the YC Ski Patrol conducted avalanche mitigation work above one of their roads. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees. Photos courtesy YC Ski Patrol.

Today the YC Ski Patrol conducted avalanche mitigation work above one of our roads. The area is outside of our ski area boundary and receives no skier traffic. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees. Two sections of road, which were controlled for traffic, were buried with an estimated 15-20 feet deep deposition pile. We’ve seen this path go big in the Spring, but we can’t recall it ever going quite this big. Photos courtesy YC Ski Patrol.

Today the YC Ski Patrol conducted avalanche mitigation work above one of our roads. The area is outside of our ski area boundary and receives no skier traffic. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees. Two sections of road, which were controlled for traffic, were buried with an estimated 15-20 feet deep deposition pile. We’ve seen this path go big in the Spring, but we can’t recall it ever going quite this big. Photos courtesy YC Ski Patrol.

Days of heavy snow and strong winds created unstable conditions in the mountains near Big Sky. This massive natural avalanche was observed on Wilson Peak north of Big Sky Ski Resort. As snow and wind subside, conditions will gradually become more stable. Photo: C. Babineau-Z

Skiers intentionally triggered this wind-loaded slope in the northern Madison Range. It broke 50' wide and 100' vertical. Photo: Anon

Skiers intentionally triggered this wind-loaded slope in the northern Madison Range. It broke 50' wide and 100' vertical. Photo: Anon

This wind slab was triggered by a snowmobiler on Buck Ridge. Although small, it's a good indication that larger slides are possible on wind loaded slopes. Photo: A. Wheeler  

Debris from an avalanche that was triggered low on the slope by snowmobilers on 2/17/19. Photo: GNFAC

On Saturday (2/16) skiers in Beehive observed "Lots of natural avalanches from Friday nights snow. Notice the large cornice sections at the base of the slope. We were impressed with the size of the cornices on the ridge. We noted no collapsing or cracking on the skin up or ski down." Photo: A. Crawford

Skiers got this small wind slab to crack at lower elevations in Beehive Basin. This may be a sign that higher elevations have this as well. Photo: H. Coppolillo