Regional Conditions for Southern Madison

From (5/17/20): "...WS - ASu - R3 - D2 - I SE face of Middle Basin Peak starting at 10,000' Estimated SZ of 30° Slab depth of about 8". We were out too late in the day and chose to ignore a number of observational warnings. We were lucky and remotely triggered the avalanche below us."

A very large natural wet slab ran on the afternoon of 5/19 at the Yellowstone Club. (Screenshot from the Y.C. Timberline chair webcam)

From obs: "Here are a few snaps from yesterday (5/2/20), looking into the Absaroka from up on Emigrant. Fair bit of smaller, pockety wet slab activity in steep, rocky terrain near the middle/upper transition. I didn't see anything larger than D2 or any activity in true upper elevation terrain." Photo: B. VandenBos

From obs: "Here are a few snaps from yesterday (5/2/20), looking into the Absaroka from up on Emigrant. Fair bit of smaller, pockety wet slab activity in steep, rocky terrain near the middle/upper transition. I didn't see anything larger than D2 or any activity in true upper elevation terrain." Photo: B. VandenBos

From obs (5/3/20): "N facing gulley, probably similar results from the Pine Creek avalanche posted on 4/29. Avalanche appears to be natural and possibly a couple days old. Ran about 400’ wide in the cone and damned up the creek with massive cement-like debris. There were more similar avalanches on N facing aspects the more I traveled. The skinning was isothermic and sloppy as each step fell through the snowpack to the ground"

From e-mail (5/1/20): "...the mountains are coming unglued with the 4 nights of no freeze and heavy rain.  My party ventured up pine creek to take a look and found this big one that ran either yesterday or last night. 

From April 30, 6 pm to May 1, 6 pm. Give Big is a fund-raising campaign to rally support for local non-profits. Get more info and donate to the Friends of the Avalanche Center's campaign here.

From obs (4/26/20): "....a wet slide from a n-ne couloir up mission creek near elephant head in the absarokas between 10-11:30 this morning. Snow did not freeze over last night and was heavily saturated early this morning before the sun rose." Photo: @laura_delray

All surfaces except the upper North faces were getting wet and sticky. We observed lots of wet loose avalanches actively happening on SE-E facing slopes. We found some cold buffy snow on north-facing slopes, not amazing skiing. There was one small crown on a steep East facing slope that looked to be from the most recent storm but everything else was loose wet. Small wind slabs from the last snow seemed to be glued down today. Photo: S. Jonas

From IG obs (4/19/20): "Saw quite a few natural wet slides back in Middle Basin over the past two days, April 17-18. Witnessed several break loose naturally after about 2pm on anything from SW to SE slopes." Photo: @joshpelczar

From obs.: "This slide appeared to have happened a few days prior to when we observed it on the 16th. When we skied the skiable terrain at Dudley Creek the snowpack was stable, though snow coverage was thin." Photo: A. Pessl

Fresh drifts broke naturally along the ridgeline which became long running wet slides. 4/17/20. Photo: GNFAC

Fresh drifts broke naturally along the ridgeline which became long running wet slides. 4/17/20. Photo: GNFAC

Pinwheels of snow indicate the surface is wet and losing strength. These were observed at Bridger on 4/17/20, caused by a skier crossing above. Photo: A. Crawford

From obs.(4/17/20): "Today while skiing at the Playground in the Bridgers my party triggered a wet slab on an ESE 33 degree slope at 7,700' (HS-ASu-R1-D1-I). No one was caught or injured. We decided to turn around as the sun was roasting the snow at 11:45 a.m., and picked a low angle slope to ski back to the trail. Skier 2 descended and popped out a slab about 10" thick and 50' wide, but the slide was slow moving at first and he was able to ski away. The slide gained momentum pretty quickly and ran powerfully about 250' down the slope." Photo: M. Talty

Skiers in Beaver Creek in southern Madison Range on 4/12/20 reported: "...There were probably a couple dozen [wet slides] in total, including several small ones that ran into Beaver Creek road. Every solar aspect had multiple slides from the past few days of warm weather, at elevations from the road up to 10000', but none were larger than any my partner and I observed near Lionhead on 4/9 (≤D2)." Photo: S. Reinsel

From IG message (4/10/20): "Huge cornice release on north face of Blackmore today around 11am. North face was not hot yet but I am guessing the rocks on the back side transferred the heat?" Photo: @graeme.emerson

From IG message (4/10/20): "My party and I observed a wet slide off of the s-se facing aspect of the Sphinx today around 1pm." Photo: @laura_delray

From email: "On Tuesday,  April 7th my group noticed a slab avalanche above our route back to the parking lot. The coordinates of the slide are 44.7184217, -111.3190452. There were snowmobile tracks directly to the right (NW) of the slide. The slide was considerably wide , more than100 yards." Photo: H. Marcussirounian

Photo: L. Ippolito

From obs (4/8/20): "My partner and I noticed this slide as we summited 10602 at approximately 10:30am, which is when I took the first photo and was able to capture the full runout. After our descent of the peak, we skinned back up to the slide to get a better look (the second photo). The slide appeared approximately a day old, with a crown 1-2 feet deep, on an almost directly north-facing aspect at 10200" elevation. It broke right along the rocks that had heated up in the sun, and was around 200-300 feet at its widest. We did not get close enough to determine which layer failed (suspected wind from the heavy wind-crust in the neighboring area), but the debris at the bottom indicated it was a wet slide." Photo: L. Ippolito

Cornice triggered avalanches in Mundy's Bowl at Bridger Bowl. Unsure if natural or skier triggered from the ridgeline. Observed the morning of 4/5/20. Appear to be dry slab/loose. Photo: T. Gittins

From obs. (4/4/20): "Rode Tepee today... Got ECTP 24 & 25 on a thin layer of SH... We also saw a few cornice drops that pulled out small slabs, new snow only..." Photo: E. Knoff

Close up of a crystal from the surface hoar layer buried 2-3 feet deep north of Bridger Bowl and throughout most of the advisory area.

From 4/3/20: "I dug a quick pit at ~7450’ on a protected east 36 degree slope - HS 240cm...ECTP18@175 on 3-6mm preserved surface hoar (photos -1mm grid)... All results repeated identically in a second ECT... Seeing the reactive SH layer I opted out of skiing anything that had a distinct rollover or was steeper..." Photo: Z. Miller

From obs 4/4/20: "Avalanche, 4th of July Couloir, Beehive. No person was caught. A dog was caught but not buried. Crown between 2 and 5 inches, based on cracking depth during ascent and pictures. Runout aproximately 120x40 yards. Estimated using gaia gps."

From obs 4/4/20: "Avalanche, 4th of July Couloir, Beehive. No person was caught. A dog was caught but not buried. Crown between 2 and 5 inches, based on cracking depth during ascent and pictures. Runout aproximately 120x40 yards. Estimated using gaia gps."

From obs. 4/4/20: "Avalanche today up portal creek. 2 1/2 ft crown and 4 - 5 ft runout. Triggered by snowmobile. Everyone was safe!"

A skier triggered this avalanche on Saddle Peak on Thursday, April 2. No one was caught. It appears to have broken under the new snow. Big avalanches in big terrain are usually unsurvivable.  Photo: GNFAC

The annual fundraiser, Give Big Gallatin Valley, will be held 6 p.m. on April 30 to 6 p.m. May 1. The Friends of the Avalanche Center are participating again this year!

This tree near the north ridge shows no signs of wind during the storm. Photo: PC

"I skied near Quake Lake today, and observed several signs that the snowpack has not adjusted to this last storm yet. While ascending, several drifts collapsed under my weight, and I observed a very recent natural slide on a wind-loaded, east facing slope at about 9200'." Photo: Sam Reinsel

This surface hoar crystal is almost 1.5 cm (each square is 2mm) and was the weak layer in a few avalanches on Buck Ridge (3/29/20). Photo: GNFAC

We saw this natural avalanche from afar. It was NE aspect and likely failed on a layer of surface hoar 1-1.5' deep. The Madison Valley is in the background. Photo: GNFAC

From obs (3/29/20): "This 44* slope failed 12” under the surface of the snow on a hard crust as we descended to help another stuck rider in a tree. Another layer exists 2” below the failed layer which persisted to follow me down the hill rupturing as fault lines as I continued rapidly down the hill after extracting the stuck rider. While the remaining slope only fractured without chasing me down the hill... "Photo: TJ Krob

Sunday (3/29/20) skiers near Fairy Lake saw this cornice collapse that ran for quite a ways in October bowl. Photo: T. Gittins

From obs. (3/29/20): "Significant wind started building mid morning, forming even bigger cornices and wind loading many slopes. Noticed this slide on an East/Northeast aspect at the back of the bowl above Maid of the Mist creek, possibly triggered by cornice fall but unknown. Happened between 9:45am and 11:30am today, as at 9:30am it was not there, and when we returned to the spot around 11:30am the slide was visible." Photo: CP

Today we rode into the Taylor Fork and Lionhead areas to remove our weather stations for the season. Photo: GNFAC

Snowfall throughout the afternoon fluctuated between S1 - S5 (during brief squalls). The winds started out moderate and from the west but calmed by the last lap ~5 pm. The new snow (from last night/this morning) was fairly well bonded to the sun/melt-freeze crust below, but the storm came in subtly upside down. Today’s snowfall (accumulating ~3” while skiing between 1-530) was light. Right along the ridgeline, we triggered 4 predictable small storm slabs 4~6” deep on the upside-down storm snow from last night/this morning, but surprisingly not on the old crust. They were each 5-10m wide x 5m long and only ran ~5m vertically. Photo: Z Miller

This is a photo of a small roof avalanche near Island Park. Warming temperatures cause water to percolate through the snow which lubricates the sliding surface. Roof avalanches have injured and killed people in the past, just one more thing to worry about. Photo: M.E. 

Dave Zinn digs a hand pit along the ridge to assess how the new snow is sticking to the ice crust. Photo: GNFAC