Island Park Area

[TROUT HUNTER]

Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Monday, December 14 at 7:30 a.m. Team Bozeman, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.

AVALANCHE WARNING

The Gallatin National Forest Avalanche Center is continuing a Backcountry Avalanche Warning for the southern Gallatin and southern Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range. New snow over the last 48 hours was deposited on an extremely weak snowpack. Today the avalanche danger is HIGH on all slopes. Areas of unstable snow exist. Natural and human triggered avalanches are likely and avalanche terrain including runout zones should be avoided.

Mountain Weather:


Last night a fast moving system dropped 2 inches in town and in the mountains around Bozeman while 6 inches fell at the Yellowstone Club and Lone Peak. The southern mountains picked up another 4-6 inches outside West Yellowstone with closer to 10 inches near Cooke City. Mountain temperatures are in the single digits to teens with strong 20-30 mph winds out of the west. Lulu Pass outside Cooke City is extra windy with gusts measuring 40-50 mph. Under mostly cloudy skies a few lingering snow showers will drop 1-2 inches in the south as winds continue from the west.

Snowpack and Avalanche Discussion:


The southern Gallatin and southern Madison Ranges, the Lionhead Area near West Yellowston, the mountains outside Cooke City and the Washburn Range:


Since Friday night the southern mountains have gotten their largest and heaviest load of snow of the season. We use snow water equivalency (SWE) to measure this weight. Over two feet fell outside Cooke City with a SWE of 1.7", and 1.1" SWE created 1 ½ feet of snow near West Yellowstone. And it was windy too. Lots of new snow plus wind creates meaty, thick slabs. Wind-loading is an avalanche problem all by itself, but in the southern mountains this weight was added to junky, unbonded, sugary facets. These wind slabs are the bully kicking sand in the face of our 90lb weakling snowpack. It doesn't stand a chance.

Faceted snow extends all the way to the ground around Lionhead-our most unstable snowpack. Around Cooke City and Taylor Fork, there are plenty of facets underlying this new snow that will fracture too. On Sunday in Carrot Basin Mark was able to get collapsing, cracking and even trigger an avalanche (see photo page) before the storm picked up; never a good sign. The southern mountains are under an Avalanche WARNING because the avalanche danger is HIGH on all slopes. Be especially mindful of not traveling underneath slide paths during these periods of high instability. Avalanches will propagate far distances and can be triggered from low on the slope.

The northern Madison Ranges:

The northern Madison Range encompasses the mountains around Big Sky. With six inches of new snow and wind the avalanche danger has risen. The viciously cold temperatures last week did the snowpack no favors. Facets grew and became weaker. Yesterday Eric and I were teaching an avalanche class on Buck Ridge where we dug a few snow pits. Some holes had two feet of facets to the ground while others were slightly better with a supportable base. But they all had lots of weak, sugary snow making wind-loaded slopes especially unstable. As evidence, a skier triggered a small avalanche on Sunday in Beehive/Middle Basin. And the ski patrol at Big Sky is battling a snowpack that only got weaker with the recent cold. Given the strong winds, new snow and unstable snowpack, today the avalanche danger is rated HIGH on all wind-loaded terrain and CONSIDERABLE on all other slopes.

The Bridger and northern Gallatin Ranges:

The Bridger Range and northern Gallatins received only a few inches of snow since Friday. But don't let that fool you into thinking things are looking up, because they're not. A wind-loaded pocket swept an ice climber to his death on Thursday (see accident page below) and a skier triggered a shallow, wind-loaded slope near Mt Blackmore on Saturday (see photo page below). These avalanches are fracturing on a layer of facets 2-8 inches thick underneath the wind slabs. It's not taking much wind to touch the snow and create unstable soft slabs. These slabs are not always obvious so I'm being conservative in my snowpack assessments. My level of confidence is low. Thus, for today, the avalanche danger is rated CONSIDERABLE on all slopes.

See photos at: http://www.mtavalanche.com/photo

I will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.

HYALITE ACCIDENT REPORT

We posted the accident report on the avalanche that killed Guy Lacelle in Hyalite Canyon. You can read it out on our Accidents page at: http://www.mtavalanche.com/accident/09/12/13

[Twisted Boost]

Everyone please be SAFE.... Brad nice work....

[TheOnlyBFC]

Do we need to start doing a rain dance in order to get that snow stable again?

[TROUT HUNTER]

Rain dance, offer up my boots as a sacrifice.... I dunno its going to be bad again up there this season. More reason to ride over in Afton I guess.

[TROUT HUNTER]

Good Morning. This is Doug Chabot with the Gallatin National Forest Avalanche Advisory issued on Tuesday, December 15 at 7:30 a.m. ProLite Gear, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.

Mountain Weather:

Yesterday, scattered showers dropped 1-2 inches in the southern mountains and a trace to 1 inch in the north. Westerly winds were strong at 20-30 mph and are getting even stronger as the arctic front finally leaves. Everyone in the northern areas was held hostage to this frigid air, but now we're free to warm up and stretch our legs. Currently, mountain temperatures are 14F, 10-15 degrees warmer than the past few days. For the next 24 hours winds are expected to blow west to southwest at 20-40 mph. Snowfall will be limited to the southern mountains with 1-2 inches falling around West Yellowstone and 2-4 inches outside Cooke City.

Snowpack and Avalanche Discussion:

The southern Gallatin and southern Madison Ranges, the Lionhead Area near West Yellowstone, the mountains outside Cooke City and the Washburn Range:

We issued an Avalanche Warning on Sunday and Monday for the southern mountains. The snowpack is weak and the 16-24 inches of snow made the backcountry unstable. Yesterday, Karl Birkeland and I went to the worst of the areas, Lionhead, to see how bad it was. Many slopes steeper than 35 degrees slid early in the storm without much snow load. We could see 1 foot deep crowns and soft slab debris on the slopes. The snowpack consists of two feet of faceted, sugary grains to the ground with the new snow capping it. We had widespread collapsing and cracking and our stability tests took little force to propagate a fracture. These are all signs of unstable, dangerous conditions. We stayed on terrain less than 30 degrees and were hyper conscious about getting underneath anything steep. These are the conditions where someone could trigger an avalanche from the bottom of a slope. Stay clear of runout zones. We took a few pictures and made a video clip showing these instabilities.

Video clip of stability tests: http://www.youtube.com/watch?v=UfwsXnndHeM

Three photos from Lionhead: http://www.mtavalanche.com/photo

In Lionhead the facets reach the ground and the snowpack isn't supportable. Fat skis are mandatory to float, and the sugary snow is so deep that I actually got face shots of facets as I snowmobiled down a hill-a first. Around Cooke City and further north the snow is more supportable, but an 8 inch layer of large, weak, and now unstable facets are underneath all this new snow. Facets are like Kryponite--they rob the snowpack of its strength. For today, the avalanche danger is rated HIGH on all wind-loaded slopes and any terrain steeper than 35 degrees. All other slopes have a CONSIDERABLE danger.

The Bridger, northern Gallatin and northern Madison Ranges:

There's a common theme with all the snowpacks in our advisory region-facets. Some areas have layers a few feet thick while others are only inches wide. No matter. They're directly under the windblown slabs and new snow. In the northern mountains they have gotten weaker with the cold temperatures. Over the weekend skiers triggered a slide near Mt. Blackmore and also in Beehive/Middle Basins. Climbers triggered slides up Hyalite and yesterday the ski patrols at Big Sky got widespread collapsing and cracking at treeline while Moonlight Basin reported a few small natural slides. Traveling and making good, smart, correct decisions regarding the snowpack is difficult right now. Facets scare me and they've been doing nothing but get weaker over the last few weeks-a trend I'm not happy with. Be conservative and second guess yourself before dropping into serious terrain. For today, the avalanche danger is rated CONSIDERABLE on all slopes.

Mark will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.

HYALITE ACCIDENT REPORT

We posted the accident report on the avalanche that killed Guy Lacelle in Hyalite Canyon on Thursday. You can read it out on our Accidents page at: http://www.mtavalanche.com/accident/09/12/13

TWEET TWEET: STAY IN THE LOOP

We're using Twitter to update folks at all hours on the snowpack, avalanches, accidents and other worthy topics. Check out our tweets at http://www.mtavalanche.com/twitter or http://twitter.com/avalancheguys.

AVALANCHE EDUCATION

1. BOZEMAN: TONIGHT at 7pm there will be a FREE one hour Avalanche Awareness Lecture at the Bozeman Public Library.

2. WEST YELLOWSTONE: TWO DAY GUIDES COURSE. On Thursday, December 17, (noon-5pm) at the Holiday Inn is an afternoon of avalanche lectures. Friday, December 18, will be in the field. Registration is NOT required. More info at: http://www.mtavalanche.com/education...s/snowmobilers

3. BOZEMAN: Montana Outdoor Science School is offering a Level 1 Avalanche Course January 7-10. For more information, contact Moss at 406-582-0526.



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[TROUT HUNTER]

Good Morning. This is Mark Staples with the Gallatin National Forest Avalanche Advisory issued on Wednesday, December 16 at 7:30 a.m. The Dance Center, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.

Mountain Weather:

Since yesterday morning the mountains near Cooke City received an additional 5 inches of snow, the mountains near West Yellowstone and the southern Madison Range received 2-4 inches, and the mountains near Big Sky received 2 inches while the Bridger Range remained dry. With this snow came strong SW winds blowing 20-30 mph. This morning at 4 a.m. winds have calmed to 10-20 mph with temperatures ranging from the high teens to low 20s F.

Today a moist southwesterly flow will bring more snow and 15-20 mph SW winds with temperatures in the mid 20s F. Mountains near Cooke City will receive 3-5 inches, West Yellowstone and Big Sky 2-3 inches, and the mountains near Bozeman will get about 1 inch of new snow.

Snowpack and Avalanche Discussion:

The southern Gallatin and southern Madison Ranges, the Lionhead Area near West Yellowstone, the mountains outside Cooke City and the Washburn Range:

Heavy snowfall on Sunday and Monday in the southern mountains including those near West Yellowstone and Cooke City combined with a weak snowpack prompted an Avalanche Warning on those days. Prior to that snowfall I experienced collapsing and cracking of the snowpack and even triggered an avalanche in the Taylor Fork drainage. On Monday Doug and Karl went to Lionhead where they observed similar conditions: widespread collapsing and cracking and numerous natural avalanches. Continued snowfall and strong SW winds have kept the snowpack near its breaking point with natural and human triggered avalanches likely on any wind loaded slope. Fractures will propagate over long distances, and avalanches can be triggered from low angle terrain in avalanche runout zones. Avoid riding under any slope steeper than 30 degrees. See a video clip of stability tests at Lionhead at: http://www.youtube.com/watch?v=UfwsXnndHeM , and photos of recent snow and signs of instability at: http://www.mtavalanche.com/photo

With more snow today, the avalanche danger is rated HIGH on any slope with wind deposited snow or any slope steeper than 35 degrees. All other slopes have a CONSIDERABLE avalanche danger.

The Bridger, northern Gallatin and northern Madison Ranges:

The snowpack in the mountains near Big Sky and Bozeman is hardly stronger than it is in the southern mountains but less stressed with less new snow. Wind loaded slopes are the exception and local ski patrols continue to trigger recently formed wind slabs. Yesterday the Big Sky Ski Patrol triggered one well below treeline breaking 1½ - 2 ft deep. In some areas the snowpack is unsupportable and highly faceted. In other areas it is more supportable but contains a layer of facets found just under snow from the past week and a half. In either case this faceted snow has been sensitive to the weight of human triggers producing many avalanches.

Without significant loading from new snow, signs of instability may not be obvious. Ask yourself: Are you looking for signs of unstable snow or stable snow? You can find either and justify poor decisions. A skier caught in an avalanche near Mt Blackmore saw all the right clues of unstable conditions but ignored them and attributed his decisions to the all the complications of being human. Fortunately he wasn't wearing his ski pole straps, and with some quick thinking he was able to dig into the bed surface and avoid being strained through trees. Today the avalanche danger is rated CONSIDERABLE on all wind loaded slopes. Human triggered avalanches are definitely possible on slopes without wind deposited snow where a MODERATE avalanche danger exists.

Eric will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.

HYALITE ACCIDENT REPORT

We posted the accident report on the avalanche that killed Guy Lacelle in Hyalite Canyon on Thursday. You can read it out on our Accidents page at: http://www.mtavalanche.com/accident/09/12/13

TWEET TWEET: STAY IN THE LOOP

We're using Twitter to update folks at all hours on the snowpack, avalanches, accidents and other worthy topics. Check out our tweets at http://www.mtavalanche.com/twitter or http://twitter.com/avalancheguys.

AVALANCHE EDUCATION

1. WEST YELLOWSTONE: TWO DAY GUIDES COURSE. On Thursday, December 17, (noon-5pm) at the Holiday Inn is an afternoon of avalanche lectures. Friday, December 18, will be in the field. Registration is NOT required. More info at: http://www.mtavalanche.com/education...s/snowmobilers

2. BOZEMAN: Montana Outdoor Science School is offering a Level 1 Avalanche Course January 7-10. For more information, contact Moss at 406-582-0526.

View the advisory, it may have photos or video not shown here.

To unsubscribe/change profile:
click here

[TROUT HUNTER]

Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Thursday, December 17 at 7:30 a.m. K2 Café and Deli, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.

Mountain Weather:

In the past 24 hours the mountains around West Yellowstone have picked up 2 inches of new snow while the northern Madison range and mountains around Cooke City received and an inch. A moist westerly flow will bring strong winds and continued snow showers to our region throughout the day. This moisture will give the southern mountains an additional 1-3 inches while the northern Madison and Gallatin ranges along with the Bridgers will pick up 1-2 inches. Strong westerly winds will reach 20-30 mph on the ridgetops while the lower elevations will see calmer winds at 10-15 mph. Temperatures will remain above average with daytime highs reaching the upper thirties and nighttime lows sinking into the teens. As a weak high pressure begins to build on Friday we can expect cooler and drier conditions.

Snowpack and Avalanche Discussion:

The southern Gallatin and southern Madison Ranges, the Lionhead Area near West Yellowstone, the mountains outside Cooke City and the Washburn Range:

It continues to snow and the winds proceed to blow. Over the past five days, more than a foot of snow has fallen around West Yellowstone and more than two feet has fallen outside of Cooke City. As the snowpack tries to adjust to this load, the stress keeps on building. Strong winds out of the W-SW along with light precipitation continue to stress this already fragile snowpack. Human triggered avalanches will be likely on wind loaded slopes and careful route finding will be required when traveling in avalanche terrain.

Jay and I spent the past two days in Cooke City working with the Park County Search and Rescue and we all experienced this weak snowpack first hand. As we toured around the Mt Henderson area we observed large amounts of whumphing and collapsing, obvious signs of instability. We also encountered easy failures with our compression tests as the large amount of new snow sheared cleanly on the thick layer of facets formed from the cold snap two weeks ago.

Similar conditions exist in the Lionhead area near West Yellowstone. Strong winds and new snow have pushed the snowpack to the point of failure. Slopes that have received wind loading will be very likely to produce avalanches.

With more snow today, the avalanche danger is rated HIGH on all wind loaded slopes. All other slopes have a CONSIDERABLE avalanche danger.

The Bridger, northern Gallatin and northern Madison Ranges:

The northern Madison Range received an inch of snow in the past 24 with strong W-SW winds. This may seem like an insignificant amount of snow, but in reality that's all it takes. As winds scour certain areas others become quickly loaded. Wind can turn this one inch into one foot in a matter of hours. Rapid wind loading is hard to predict and can turn safe slopes in the dangerous avalanche zones very quickly. Yesterday, a group of snowmobilers on Buck Ridge reported heavy wind loading on east facing slopes with notable signs of instability. The most obvious sign was an avalanche they remotely triggered from 30 ft away. This avalanche broke up to three feet deep on a SE facing slope and was a wind slab deposited on facets. The Big Sky Ski Patrol also reported triggering an avalanche on a SE facing slope at 8,000 ft. This slide released on a ski cut 18" deep and slide path ran as big as it has in years.

The northern Gallatin Range along with the Bridgers have received less snow over the past week, but continue to produce avalanches. Wind slabs overlaying facets continue to be the main problem. Yesterday, Mark went avalanche hunting on to Mt Blackmore and got what he was looking for. Mark triggered an avalanche on the same slope that a skier was caught on over a week ago. This avalanche fractured a foot deep, 100 ft across and ran over 200 vertical. Today, dangerous avalanche conditions do exist on all wind loaded slopes. Careful snowpack evaluation, cautious route finding and conservative decision-making are essential when traveling in the backcountry.

See video of Mark's avalanche: http://www.youtube.com/watch?v=BmXFbnlBVK4

Human triggered avalanches are definitely possible on slopes without wind deposited snow where a MODERATE avalanche danger exists. Today the avalanche danger is rated CONSIDERABLE on all wind loaded slopes.

[TROUT HUNTER]

Mountain Weather:

In the past 24 hours three inches of new snow has fallen in the Bridgers with two inches falling in the northern Madison Range and the mountains around Cooke City. Only a trace of new snow fell in the northern Gallatin Range and mountains around West Yellowstone. Ridgeline winds have been out of the W-SW at 25-35 mph. Temperatures are in the high 20's to low 30's.

Today we can expect more warm weather with valley temperatures climbing into the 40's with upper elevations getting well above freezing. A chance of valley rain and mountain snow will continue through the day. Winds will remain constant along the ridgtops at 15-25 mph out of the W-SW. Another storm is scheduled to move into southwest Montana tomorrow bringing a better chance of measureable precipitation.

Snowpack and Avalanche Discussion:

The southern Gallatin Range, the entire Madison Range, the Lionhead Area near West Yellowstone, the mountains outside Cooke City and the Washburn Range

Two weeks ago I imagined a linear progression of the snowpack from good in the northern Madison Range to terrible in the south near Lionhead. My vision held true for a short period of time, but now has disintegrated as weak and unstable conditions have formed across the entire Madison Range.

Yesterday Doug and I toured around the Taylor Fork area and found widespread instability. We encountered settling slopes and numerous natural avalanches. These natural avalanches varied in size and occurred on a variety of aspects with east facing being the most predominant. The largest natural avalanche we studied occurred on an E facing slope at 9,100 ft. This slide broke 200 feet across, two feet deep and consisted of a hard wind slab sitting over a very weak layer of facets. Cohesionless, sugary facets are pervasive throughout the bottom half of the snowpack, which is now capped by a thick slab ranging from 10-18 inches in thickness.

Photo of Taylor Fork avalanche: http://www.mtavalanche.com/images/09...-avalancheSnow profile: http://www.mtavalanche.com/images/09...k-crown-profil

Conditions in the southern Madison Range outside of West Yellowstone are no different. A thick slab sitting over 12-18 inches of rotten, faceted snow has made for extremely unstable conditions. All slopes steeper than 35 degrees should be avoided.

In the northern part of the Madison Range a skier in Beehive Basin reported an avalanche on the east facing slope that sits between Beehive and Middle. This slide broke 30 feet across and ran 400 vertical feet. It appeared to be triggered by a skier initiated cornice drop. Large surface hoar was also observed in this area. With more snow and wind on the way this surface hoar layer could add more problems to this already troubled snowpack.

The mountains outside of Cooke City seem to be a bit more stable. Snowmobilers riding steep slopes indicate the snowpack has some strength. However, thick slabs sitting over weak layers do exist. With more snow and wind on the way we can expect the avalanche danger to increase.

Today, human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.

The Bridger and northern Gallatin Ranges:

Stability is a shade better in the Bridgers and northern Gallatin Range, but not by much. The waiting game is on to see if small amounts of new snow and warmer weather and will help heal the snowpack or if a large snowfall will move the snowpack past the tipping point. I'm guessing it will take a major load, 2-3 feet of new snow, to create a large scale natural avalanche cycle. Only time will tell.

In the meantime, the structure of the snowpack has the ingredients necessary to produce avalanches. Steep slopes, slabs and weak layers are prevalent throughout both ranges. The final ingredient needed to produce avalanches is the proper trigger. Wind loaded slopes steeper than 35 degrees will like produce avalanches with a human trigger. With more snow and wind on the way the avalanche danger will increase.

Today a COSIDERABLE avalanche danger exists on all wind loaded slopes. All other slopes have a MODERATE avalanche danger.

[TROUT HUNTER]

Mountain Weather:


A split jet stream has produced a large high pressure system that has now encompassed the entire state of Montana. High pressure systems involve large masses of air that rotate clockwise (in the northern hemisphere) and result in sinking air and stable conditions. High pressure traps cold air in the valleys and keeps warmer air aloft making for striking temperature inversions. This trapped cold air can produce dense valley fog and even light precipitation in the valleys as moisture is condensed out of the air.

Southwest Montana will remain under high pressure for at least the next 24 hours making for clear skies and calm conditions. Winds will be light along the ridgetops at 5-10 mph out of the S-SE. Valley temperatures will remain cold with lows in the single digits and highs around twenty. In the mountains, temperatures will feel almost tropical with highs in the upper twenties to low thirties and lows around ten degrees. It looks like we will be moving into an unsettled weather pattern starting Wednesday and continuing into the latter part of the week.

Snowpack and Avalanche Discussion:


The Gallatin and Madison Ranges, the Lionhead Area near West Yellowstone, the mountains outside of Cooke City and the Washburn Range:

Slabs sitting over weak, faceted snow continue to be a constant problem from the northern Madison and Gallatin Ranges all the way to Cooke City. A rider in the Taylor Fork on Saturday experienced cracking and collapsing and even got small chunks of snow to move on low angle slopes. These are obvious signs of instability that are not to be ignored. Unfortunately, signs of instability will not always be this noticeable. When dealing with a weak, unpredictable snowpack such as the one we have now, each individual slope should be evaluated before being ridden on.

Doug was riding in Cooke City yesterday and witnessed numerous human triggered avalanches and experienced cracking and collapsing as he toured on low angle slopes. One slope that avalanched and caught a rider had 10-20 tracks on it when it slid. This is a perfect example that tracks on a slope can not guarantee stability. It's important to be wary around rock outcroppings and places where the snowpack will be thinner. These areas are likely trigger points that will fail and potentially pull out larger areas around them.

See Pictures of Avalanche:http://www.mtavalanche.com/images/09...te-avalanche-2

See Video:http://www.youtube.com/watch?v=4CPi1...layer_embedded

Just because the weather has improved doesn't mean the avalanche hazard has. Always travel one at a time on steep slopes and make sure everyone in the party has rescue gear and knows how to use it.

For today, human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.

The Bridger Range:

Quiet weather has helped stabilize the snowpack in the Bridgers. A lack of significant snowfall over the past few weeks has left the pack weak but not terribly unstable. In most places there is not enough weight to propagate a fracture and produce a slab avalanche, though avalanches are still possible on steep wind loaded slopes.

A new arising problem in the Bridger Range is the weak snow that is forming at or near the new snow surface. Low density snow from our last snow event combined with warm days and cold clear nights is a perfect formula for producing both surface hoar and near surface facets. Both of these fast forming weak layers can easily be preserved under future new snow and have the potential to be a hazard in the snowpack for weeks. With a snowier pattern in the forecast this will be something to look out for.

For today, a MODERATE avalanche danger exists on all slopes.

Doug will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.

AVALANCHE EDUCATION

1. WEST YELLOWSTONE

Snowmobilers and Skiers: Saturday, January 2 from 12-5 pm at the Holiday Inn is avalanche lectures. Sunday, January 3 will be an all day field session for both skiers and snowmobilers. $30 suggested donation. No sign up required. http://www.mtavalanche.com/education...s/snowmobilers

2. BOZEMAN

Level 1: 7-10 January, Montana Outdoor Science School is offering a Level 1 Avalanche Course. Instructors are Angela Patnode and Jay Pape. For more information, contact Montana Outdoor Science School at 406-582-0526.

3. BOZEMAN

Level 1: American Avalanche Institute is offering a Level 1 Avalanche Course January 22-24, 2010 at Bridger Bowl. Get more information and register at: www.americanavalancheinstitute.com

4. FOUR CORNERS

Rescue Lecture: On Tuesday, 26 January, the Gallatin Valley Snowmobile Association is having it annual Chili Feed at 6:30pm in the Groomer Shack. At 7:00 there's a free Avalanche Rescue Talk. http://www.mtavalanche.com/workshops/calendar

5. BOZEMAN

Basic Avalanche Workshop: The Friends of the Avalanche Center and MSU are offering a Basic Avalanche Awareness Class the evenings Wed, Thur, 27 & 28 January with a field day on Saturday, 30 January. $25 donation. No sign up required. http://www.mtavalanche.com/education/classes/basic

[TROUT HUNTER]

Good Morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Monday, January 25, at 7:30 a.m. Bridger Bowl, in cooperation with the Friends of the Avalanche Center, sponsor today's advisory. This advisory does not apply to operating ski areas.

Mountain Weather:


A massive low pressure system has moved out of our area and is now sitting over the midwest, continuing to suck cold air from Canada southward into Montana. This low pressure system was responsible for delivering 2-3 inches of new snow to the Bridger Range in the past 24 hours with a trace to 2 inches falling over the rest of the advisory area. Winds have been out of the NW at 15-20 mph, but will calm and shift to the west as the day progresses. Cold and dry conditions will exist over our area for the rest of the day with highs in the 20's and lows in the single digits.

Snowpack and Avalanche Discussion:


The Madison Range, Southern Gallatin Range and the Lionhead area near West Yellowstone:

"What a relief!" is the phrase I heard more than once commenting on the skiing and riding conditions from Big Sky to West Yellowstone. With a foot of new snow over the past few days, backcountry enthusiasts' spirits have been heightened but so has the avalanche danger. This new snow sits on top of multiple layers that hold the potential for failing, propagating and producing avalanches. A major area of concern is fresh wind slabs that have formed at mid to upper elevations. Both Big Sky and Moonlight Basin Ski patrols have reported soft wind slab avalanches being triggered by explosives and ski cuts and a wind slab avalanche being triggered in the backcountry is very possible.

In addition, there is still a chance that deep slab avalanches could propagate on the weak faceted layer sitting 2-3 feet below the snow surface. This pesky and persistent weak layer has existed within our snowpack since the early part of the season and continues to produce low scores on stability tests and is the culprit for the occasional human triggered avalanche. A new player in the game is layer of buried surface hoar that sits roughly 40 cm below the surface. This layer was discovered by Doug and his partner as they toured around the Taylor Fork yesterday. Although this layer is not widespread, it did produce extremely easy test scores with an ECTP 12, Q1 and CT 5, Q1. This layer produced loud whumpfing and shooting cracks that extended 200 feet from Doug's ski tips, prompting Doug to test the slope further. The slope failed and avalanched on his first test jump. This touchy surface hoar layer is most prevalent on shady slopes that have not received strong winds. For today, a CONSIDERABLE avalanche danger exists on all slopes.

Northern Gallatin Range, the Bridger Range, and Mountains around Cooke City

Holy Cold smoke! With 16 inches of new snow in the past three days, the Bridger Range received more snow than any other Range in our advisory area. This produced great skiing and luckily very few avalanches. Our main concern is the development of wind slabs forming close to the ridgeline. With plenty of new snow available for transport and winds blowing in the 20's for most of the day yesterday, these freshly formed wind slabs will easily fail under the weight of a skier or rider. The possibility of triggering a deep slab avalanche on buried facets remains, but is less likely.

The northern Gallatin Range and mountains around Cooke City hold similar conditions. Face shot skiing was reported on Mt Ellis yesterday with very few signs of instability. I skied Mt Ellis two days ago and found plenty of weak snow but no slab. This could all change very quickly if the wind decides to blow in this area. Fresh wind slabs on steep, mid to upper elevation slopes hold the highest potential for producing avalanches. A skier in Cooke City reported good, stable skiing on slopes less than 35 degrees with no new slab avalanche activity visible. He did however mention that deep buried facets remain a major concern and avalanches that fail on this layer will be large and destructive. With the new snow and strong winds over the past few days a CONSIDERABLE avalanche danger exists on wind loaded slopes. A MODERATE avalanche danger exists on all slopes that have not received wind loading.

Doug will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or email with your observations. You can reach us at 587-6984 or email us at mtavalanche@gmail.com.