Blog List

Doug Chabot
4/16/2015

April 16, 2015

Greetings:

What a strange year it has been.  We started strong with many storms and early season snow, followed by spring weather in February and March and then one of the biggest snowfalls of the season yesterday. Go figure. Although skiing and snowmobiling conditions were bipolar, the snowpack was generally stable with more days of “Low” avalanche danger than any of us can remember.

Eric Knoff
4/15/2015

Spring skiing can be some of the best of the season. Good snow coverage, warmer weather and more predictable snow stability (at times) can lead to unmatched conditions. While spring skiing can be the best, it can also hold avalanche hazards not encountered during the colder parts of winter.

As snowpack and weather transition into a warmer and wetter spring pattern, there are a number of avalanche variables to pay attention to.

Eric Knoff
3/12/2015

Five Easy Steps to Safe Backcountry Riding

By: Eric Knoff

Gallatin National Forest Avalanche Center

Eric Knoff
3/12/2015

The snowpack changes from year to year, even day to day but, the terrain on which snow falls remains constant. Understanding and recognizing avalanche terrain are critical tools for safe decision making in the backcountry.

During stable snow conditions, riding in avalanche terrain is safe and acceptable. When snow conditions are unstable, avoiding steep slopes and avalanche run out zones is key to avoiding avalanches.

Doug Chabot
1/20/2015

Published in the April 2015 issue of The Avalanche Review.

Lynne Wolfe, editor of TAR, asked me to jot a few thoughts down on how we manage surface hoar once it is buried. This is the email I sent back to her.

Doug Chabot
1/19/2015

Published in the January 2015 issue of Carve.

R: RESTRICTED. Under 17 requires accompanying parent or adult guardian.

An R-rated film includes “…adult themes, adult activity, hard language, intense or persistent violence or other elements, so that parents are counseled to take this rating very seriously.” Sidecountry is more serious than the most serious film because people of all ages can die in the sidecountry, especially youth that lack adult supervision or perspective. A young adult sneaking into a theater might face consequences if caught, but heading out-of-bounds of a ski area into the sidecountry is an entirely different level of risk.

Mark Staples
12/31/2014

Published in the February 2015 issue of The Avalanche Review.

The Class

Doug Chabot
12/31/2014

By Doug Chabot

Published in the February 2015 issue of The Avalanche Review.

As an avalanche forecaster and educator I pay close attention to teaching the recreating public about heuristic traps, aka human-factors, and their role in avalanche accidents. A powerful voice is Powder Magazine’s riveting five-part Human-Factors series which did a great job of pointing out those traps.

Doug Chabot
12/8/2014

Published in the Dec 2014 Carve

Put your shovel in the snow!

This simple act could save your life. Pausing to assemble your shovel and dig a few scoops can sometimes reveal a hidden but, once exposed, obvious weak layer. Taking a few more minutes to perform an Extended Column Test (ECT) may give you strong evidence of unstable slopes. When conditions seem good most people have already made their decision to ski or not by the time they reach the top of a slope, but an ECT might change your mind and save your life. Conversely, if you decide to not ski because of dangerous conditions there is no need to dig. Regardless of experience, if we play in avalanche terrain we should hunt for instability.

Eric Knoff
11/12/2014

             There are no stoplights in the backcountry. The decision to ride into uncontrolled-avalanche terrain is a personal one with risks and rewards. Done correctly, pinning the throttle through a field of untracked powder or climbing a steep mountain face can produce unmatched excitement, but riding in avalanche terrain can produce severe and sometimes deadly consequences.

Doug Chabot
10/22/2014

Presented at the 2014 ISSW in Banff, Canada.

Conducting stability tests in avalanche terrain is inherently dangerous since it exposes the observer to the potential of being caught in an avalanche. Recent work shows that such exposure may be unnecessary since the results of extended column tests (ECTs) and propagation saw tests (PSTs) are largely independent of slope angle, allowing for data collection in safer locations.

Eric Knoff
10/22/2014

Presented at the 2014 ISSW 

In recent years, the propagation saw test (PST) gained popularity for both avalanche professionals and backcountry recreationalists. A limiting factor of the PST is the additional time required to isolate a column on the sidewall of the snowpit. Since I often have limited time to dig multiple pits during a work day, this past season I examined the effectiveness of conducting cross-slope PSTs (CPST). The CPST is simply a PST done across, rather than up, the slope. It is more efficient than the PST, particularly after conducting an extended column test (ECT).

Mark Staples
10/21/2014

Presented at the 2014 ISSW in Banff, Canada.

For the last 24 years, the Gallatin National Forest Avalanche Center has achieved many successes in snowmobile avalanche education but many challenges remain. Building on the efforts of many others and the work outlined by the GNFAC at an ISSW twelve years ago, our snowmobile education has evolved considerably. Live recoveries, unheard of only 10 years ago, seemingly occur every winter now. 

Doug Chabot
4/15/2014

Powder Magazine

Winter is in the rearview mirror and spring is gaining momentum but we cannot forget about avalanches. As the seasons change so do the types of avalanches. There are two ways to trigger avalanches: stress the snowpack or weaken it. Dry slab avalanches are common in winter and occur when too much weight (stress) is added to the snowpack. Under a heavy load of new snow, windblown snow or skiers, layers collapse and avalanche from this added stress. In spring the snowpack loses strength and weakens when melting water breaks down snow crystals and provides lubrication between layers. Some types of layers are more prone to this type of weakening and this season the western US has one of the worst: depth hoar.

Mark Staples
3/20/2014

 

                We have a deep slab avalanche problem throughout the advisory area. Adjacent mountain ranges likely have this problem as well. It exists because the entire winter’s snowpack rests on a layer of facets near the ground. It produced avalanches in late December and early January and again following heavy snowfall in February and early March. This weak layer of facets, formed in early December during extreme cold weather will be a concern for the rest of the season.

Doug Chabot
3/12/2014

Published in Carve, March 2014

In a career of 15 years I have investigated a lot of avalanches. The most interesting ones are unintentionally triggered and are intriguing because they usually involve a series of decision-making failures only obvious in hindsight. This winter has been rich in such experiences. Folks have triggered many avalanches and a few have been caught and one died. Over President’s weekend three skiers were in an avalanche they triggered while skinning up Beehive Basin to the north of Big Sky. Small mistakes stacked up to create a potentially deadly situation. All too often my avalanche accident investigations involve a fatality. This accident ended with a rescue and only minor injuries. Although terrifying and sobering for those involved, I am excited about the possibility to learn and pass along the lessons to others. Avalanches involving buried skiers that don’t end tragically are rare and, to an avalanche educator, a gift.

Eric Knoff
2/20/2014

 

I'm dreaming of fresh and stable powder when the alarm cuts through the early morning silence like a buzz saw. I quickly roll over and check my phone.

It's 3:15 a.m.

There is no hitting snooze for fear that I'll fall back into the grip of sleep. I will myself out of bed to start my day.

Doug Chabot
1/31/2014

Published in Carve, February 2014

I envision that should I ever be buried in an avalanche my partner will locate me quickly, put together his shovel and dig like a maniac. He will be anaerobic, spittle drooling from his mouth, sweat burning his eyes and he’ll be puffing like a locomotive. His heart rate will be in maxxed, his face red and ears ringing. I know this because I carefully chose my backcountry partners. They will give 110% of themselves to save me if I’m buried. They are mentally, emotionally and physically tough.

Eric Knoff
1/22/2014

 

From the time snow crystals fall from the sky to time they melt in the spring, the shape and structure of each crystal never stops changing. This is known as snow metamorphism. 

Snow metamorphism determines if individual snow crystals are rounding (becoming stronger) or faceting (becoming weaker). The relationship between snow crystals ultimately dictates what kind of layer, strong or weak, is formed. The interaction between individual layers determines snowpack stability.

Doug Chabot
1/22/2014

Cooke City has a deep slab problem: a 7+ foot thick snowpack resting on a layer of facets.  This recipe might be a preview for the rest of our forecast area since there are still months of winter left.  I tried to explain the problem with the analogy below. A proper, technical definition can be found on the Colorado Avalanche Information Center's website.

DEEP SLAB INSTABILITY: an analogy