Ben at the 2017 Grand Traverse |
A letter of protest to surface hoar
Unusual cloud layers and unusually widespread surface hoar layer in mid January. Photo courtesy of MSF Films |
Then more snow came, and it formed a soft slab above you, and your behavior started getting erratic through the last week of January. We saw lots of natural avalanches, we saw avalanches breaking in dense aspen groves and on low angle slopes, and we saw slides remotely triggered from flat terrain.
A slide on Mt. Emmons that caught a skier off guard. |
Most of the persistent slab avalanche activity in late January was on surface hoar. Read this observation for some caveats to this diagram. |
The New Year storm….already historic and still counting!
The New Year storm….already historic and still counting!
Credit: Xavier Fane |
Credit: Chris Miller |
Credit: Xavier Fane |
Back in the flow. Zach Guy, CBAC Director
The Western U.S. is coming out of a long drought and the atmospheric snow guns have finally replaced the artificial ones that were building our ski area’s snow base. With snow comes avalanches. There were two avalanche fatalities in the West over the weekend: a skier in closed terrain in Mt Rose Ski Tahoe on Saturday, and a backcountry skier near Cooke City, MT on Sunday. We send our sincere condolences to all of those affected by these tragedies. Here in Colorado, there has been a stroke of divine luck, with a number of multi-party burials that resulted in profound learning lessons, rather than fatalities. A trio of skiers in Butler Gulch, near Berthoud Pass, were all caught and buried on Saturday. Two of them were only partially buried and were able to rescue the third. On Sunday, a skier was caught in a slide near Red Mountain Pass and two snowmobilers were fully buried but rescued by their group near Steamboat. On Monday, a snowmobiler was buried near Crested Butte. Needless to say, avalanche season is upon us.
The search area for the avalanche victim at Mt. Rose Ski Tahoe. Photo courtesy of Washoe County Search and Rescue.
The Elk Mountains have been in a favorable zonal flow pattern since December 6th. CBMR reported 18” of snow in the past week, and some of our backcountry areas have picked up almost twice that. More is on the way this weekend. Anytime we have periods of dry weather, especially early season, our snowpack develops weak layers. Once we start getting back into the storm track, those weak layers get loaded and stressed, creating avalanche concerns. Sometimes these avalanches can act in surprising or unique ways, like being triggered from long distances away or from flat terrain. This video demonstrates the challenging nature of persistent slab avalanche problems, where there is a cohesive slab over a persistent weak layer.
A group of 3 skiers were buried in this slide in Butler Gulch, CO on Saturday. Photo courtesy of CAIC.
It is easy to get caught up in the powder frenzy this time of year. We’ve all been itching to arc those graceful turns down powder filled slopes or throttle through deep pillows and faceshots. But we need to draw a line and stay behind it. One of my mentors up in Montana recently discussed how taking one step back from the line is insufficient. “To ensure a lifetime in the mountains, it is a matter of taking three or four steps back.” The CBAC got an observation yesterday, reporting signs of instability, which concluded with: “Suspect a successful tour could have been had with proper navigation today, but the instabilities spooked us, especially while navigating unfamiliar terrain. We opted to head home.” I applaud that kind of decision making. There isn’t any kind of steep or deep powder run that exceeds the reward of returning home safe at the end of the day.
Snow profile showing unstable results near Crested Butte. 12/11/16
If you are new to the area or visiting, make sure you tune into our avalanche advisories at www.cbavalanchecenter.org. Our forecast team has been in frenzy the last couple weeks to keep tabs on the state of the snowpack. On Sunday, after a big pulse of moisture plowed through the night before, we had all three of our forecast staff up three prominent drainages surrounding our town digging into and documenting the snowpack to help aid in your backcountry decision making. Use our website and observations page as a resource! Give those guys a pat on the back for their often stressful and sleep deprived work during the holiday season. You can just sense the anxiety in Havlick’s voice in this video, and I bet the poor guy hasn’t done his laundry in 2 weeks now. And thank our ski patrollers at CBMR and respect roped off or closed terrain. Those guys and gals are working hard to mitigate avalanche hazards to get terrain open.
Thanksgiving and avalanches
Thanksgiving and avalanches. By Zach Guy
Shooting cracks are a sign that the snowpack might have taken a few too many scoops of mashed potatoes and stuffing.
It has been a wonderfully warm and dry fall, which is hard to complain about. But if we can be brutally honest with the weather gods, fall really was starting to wear out its welcome, and we are happy to open the door to winter. There’s nothing quite like surfing over powder, so it’s time to dust off those skis, find your beacon, shovel, and probe, and start tuning into our daily avalanche reports.
Early season skiing and riding comes with some challenges and risks. The snow coverage is still quite shallow, so striking rocks and logs are tough to avoid and they can end your season pretty quickly. My strategies include getting on the fattest skis I can find, riding like a gaper in the backseat, and using releasable bindings in case my tips dive under a log or rock. I’ve seen a few too many broken tib-fibs from early season riding. And of course, we all want to go to where the snowpack is deepest, which can open the doors to another scary threat: avalanches. This time of year, the slopes holding deep and continuous coverage often carry the greatest risk of triggering an avalanche. It is almost impossible to go through fall without a shallow, crusty, and faceting foundation forming on the ground. Then once we start building a deeper snowpack, it creates a persistent slab avalanche problem above these layers.
Skier triggered slides in Red Lady Bowl
I like analogies, so let’s compare our current year’s snowpack to your most recent Thanksgiving celebration. You probably avoided food all day, maybe even went for a turkey trot to work up an appetite in preparation for the big feast. A significant drought, indeed. That left you weak and frail, just like the lingering snowpack layers that survived our fall drought. Then once dinner time (i.e. winter time) rolled around, you started off at a decent pace. Snacked on some hor devoirs, some salad, maybe some of your Uncle’s famous deviled eggs or your Grandma’s bean dip. Our first few storms behaved in similar fashion, fairly small and steady loads, with a handful of isolated avalanches. Nothing too scary yet. Then it is dinner time: you go for the mash potatoes, stuffing, turkey, green bean casserole, and of course drown it all under gravy. Extra rolls? Why not? Whammo. That’s a heavy load, just like our last storm, which dumped almost 2 feet in places. Both scenarios are dangerous. You could collapse on the couch just as easily as you could collapse those fragile weak layers near the ground. During and after the storm, we saw both natural and skier triggered avalanches, some quite large and surprisingly wide. As of Tuesday night, I’m expecting we’ll see evidence of a lot more avalanche activity as we get better visibility over the next few days. So tread carefully out there, and check the avalanche report before you go out. So what’s next for our snowpack? Does it reach for another plateful of mashed potatoes before slamming down some pumpkin pie and faceplanting onto the floor? Or does it slowly nibble at the leftover turkey and try to stay awake for family charades? Only the weather can dictate that one. But you can be the captain of your risks by making rational decisions and practicing your rescue skills. Is it a coincidence that this Friday night is our Annual Avalanche Awareness Night, with the theme “Human Factors and Decision Making”? Or that Saturday is our annual Beacon Brushup, a free and valuable opportunity to dial in your rescue skills for the winter? I think not. See you there!
Human Factors and Decision Making
Human Factors and Decision Making
By Zach Guy, CBAC Director
This year’s theme to CBAC’s Avalanche Awareness Night on December 2nd, 2016 is “Human Factors and Decision Making”. Almost all avalanche accidents are triggered by the victim or a member of their group. We are the ones who expose ourselves to avalanche risks, and often it is our own decision making that puts us into trouble.
Although humans have been pondering our methods of thinking and rationalizing for centuries, Ian McCammon has been instrumental in research in the avalanche industry. I was fortunate enough to have Ian as a course instructor and mentor for my AVPRO class about 7 years ago, and caught up with him to ask a few questions about human factors and decision making.
Ian McCammon. Photo courtesy of POWDER magazine. |
Zach Guy: Ian, you have a PhD in mechanical engineering, and a Master’s in Material Science. In the avalanche world, you are well known for your research on human decision making. What inspired your shift in focus from physics towards psychology?
Ian McCammon: My own journey started years ago when a friend of mine died in an avalanche. Using tools from my engineering background, I searched for statistical trends in hundreds of past accidents and found that the circumstances of my friend’s death followed a pattern that repeated itself again and again: risk perception for certain groups was distorted under certain conditions.
Zach: In 2002, you published a paper on heuristic traps and how these human factors affect our decision making and influence avalanche accidents. The acronym “FACETS” (Familiarity, Acceptance, Consistency, Experts, Tracks/Scarcity, and Social Facilitation) has been adopted by essentially every avalanche course around the country to introduce these human factors. My talk at Avalanche Awareness Night will dive into some of these factors and a close call that I had back in 2009. In your research or simply from personal experience since then, are there any other human factors that you think backcountry travelers should be aware of?
Ian: Fatigue is an important physiologic factor that influences our decision making. When you are tired, dehydrated, hungry, cold or just sucking air from a long ascent, it’s hard to judge hazards objectively. And just like the FACETS cognitive traps, fatigue is dangerous because people consistently underestimate how profoundly it can impair their judgement.
Zach: You developed some systematic tools to help backcountry travelers overcome our human biases, such as ALPTRUTH and Lemons. Do you have any other personal tips or strategies that you use in your ski tours for overcoming the inherent biases in the way our brains process information and make decisions?
Ian: ALPTRUTh was designed to do two things. First, it stops you at the cusp of a decision – it breaks the momentum that sometimes carries people into trouble. Second, it helps you see how your group’s decision will be viewed should an accident take place – a process called a pre-mortem. There are other ways to do this, and my hope is that new and better tools will emerge from research into this important area.
Another strategy in addition to APLTRUTh is to choose your partners wisely. Choose people with the wisdom to stop the group’s momentum at the right times and reconsider evidence and the opinions of the group. If they can do that, it’s going to be less frustrating and more effective to manage risk as a group.
Zach: Social media has exploded since your original research 15 years ago. We have a presenter who will be touching on this subject at Avalanche Awareness Night. With Facebook, Instagram, Youtube, etc., the entire internet is watching what we do in the backcountry. What is your take on the impact of social media on our decision making, and do you suggest or have any strategies for handling its potential influences?
Ian: This is a fascinating and worthy topic for research. I am glad you have a presenter exploring this subject. Some folks are choosing to literally create their social identities in near-real time as their decisions and outcomes are posted and amplified across an audience of friends and potential critics. An important question for each of us is how much are we willing to allow that unseen audience to shape our critical decisions.
Zach: Any parting words for our Colorado audience that recreates in the deadliest snowpack in the country?
Ian: To paraphrase Baltasar Gracian: Know your major weakness. If you do not understand it, it will rule you like a tyrant.
Zach: Thank you Ian for sharing your wisdom, and for your contributions to the avalanche industry.
Join us at CBAC’s Avalanche Awareness Night for more great presentations on human factors and decision making.
Backcountry Etiquette
The slide on Taylor Mountain near Teton Pass. The skier was conducting an intentional ski cut, but the slide went much larger than expected. Photo courtesy of TetonAT.com |
Debris piles were 10-12 feet deep in the Coal Creek drainage, a launching and exit point for many backcountry skiers looking to get into relatively safe terrain. Photo courtesy of TetonAT.com. |
So what does backcountry etiquette mean? Simply put, be aware of your actions and their consequences in the backcountry, because they don’t solely affect you. If you trigger an avalanche, will it affect someone down slope of you? Communicate with people you encounter on your tours; discuss your routes and how you can avoid crossing above or below each other. A few days ago, I found myself on top of the Anthracites on a powder day with over a dozen powder-starved locals eager to drop in. All of the groups did a great job of communicating and divying up the terrain so that we didn’t all get bunched up on one avalanche path. If you see a group climbing up your intended descent route, wait for them or choose another route. Its simply not worth putting them in the line of fire. Cornice drops and ski cuts can be a great slope test, but are you absolutely sure that no one will be affected below you? Think about the size and possible extent of an avalanche that you could trigger. Under some conditions, a slide on Red Lady Bowl or above Peanut Lake Road or on Snodgrass could run across roadways of innocent commuters. And just as importantly, if you get injured or killed in a slide, the impacts reach far beyond just you. You have family members, friends, and community members that will be deeply impacted.
This is a natural avalanche that crossed Peanut Lake Road and the nordic track 2 winters ago. |
Mt. Baldy
Date of Observation: 10/25/2015
Name: Dustin
Aspect:
Elevation: Above treeline
Avalanches: Observed a previously triggered point-release on a W – NW aspect near WSC bowl on Baldy. Likely occurred 10/23.
Weather: Warm and clear during the days with clouds increasing Sunday.
Snowpack: Most snow accumulation is around 11,000 feet and above. Little avalanche potential otherwise as there is simply not enough snow to form slabs. The exception is up high in very windloaded areas. A snowpit around 12,700 feet on a E-facing windloaded slope (Treasury) showed a pack of 110 cm with uniform layering . ECTN. Typical mixed bag of conditions elsewhere where snow had accumulated with suncrusts, wind crusts, and dry snow in the suspect areas. Did find basal crust on rocks under dry snow on N-facing slopes around 11,000.
Spring Travel Advisory 2015
Issued 4/6/15 by CBAC
Spring season is a great time of the year to get into the mountains and generally offers better stability and more manageable avalanche problems for backcountry travelers. However, avalanches conditions can still be dangerous during spring, and there are several kinds of problems you should continue to monitor and assess in you springtime adventures.
-Storm instabilities
Spring snowfall will usually fall on some form of crust. These surfaces do immediately bond well. Anytime a slab of new or windblown snow forms, expect touchy conditions during and shortly after the storm. New snow becomes especially sensitive as the sun comes out immediately after the storm and quickly consolidates into more of a storm slab. Expect leeward and crossloaded features at higher elevations to hold thicker and more sensitive windslabs following a storm with moderate or strong winds. These kinds of instabilities are generally short-lived during the springtime, but can last for several days after the storm on shaded aspects or higher elevations. The best strategy is to monitor how much snow accumulates during a storm and ease into small and manageable terrain until you’ve assessed how large and how sensitive new slabs are. Be wary of windloaded slopes and avoid heavily windloaded features following a significant storm. The Schofield Pass SNOTEL, which is northwest of town, and the Butte SNOTEL, which is on Mt. Crested Butte, are local remote snow sensors that update hourly. Storm or wind slabs are most problematic over consequential terrain with cliffs, gullies, long vertical, or rocks and trees.
-Wet avalanches
When the sun (or rain) comes out after a spring storm and moistens the new snow, loose wet avalanches become frequent on any slope steeper than 35 degrees, and these point releases typically fan out and entrain all of the new snow down to previous crust layers. These are usually small and predictable, but can carry significant mass after a large storm or in terrain with significant vertical relief. They can also run when old snow looses cohesion as crusts thaw, and have potential to entrain a large amount of snow during prolonged warm-ups. Wet slabs can be a larger and more dangerous problem. These are caused by liquid water percolating to and compromising the strength of buried weak layers. This year, our snowpack is about a month ahead of schedule, meaning our April avalanche problems are more typical of May problems. Most slopes facing east through south through west, as well as lower elevations that face north, have seen water run through the entire snowpack and have already been delivered the dry to wet “spring shock”. These slopes saw a wet avalanche cycle in mid-March. A number of these slopes have matured into a stable, spring snowpack, but it is difficult to identify which ones could still be harboring the threat of a wet slab. Northerly facing slopes near and above treeline have seen less, if any, meltwater, and still primed for wet slab activity when temperatures and the higher sun angle turn on the water factory. Last year, these slopes began their wet slab cycle around late May to early June. The size of wet slabs failing on deeply buried weak layers will be likely be large at these elevations. Wet slabs are most likely to occur during prolonged warm-ups and/or following multiple nights without a good refreeze. If we see a dust-on-snow event, this will expedite surface warming. Wet avalanche danger is usually lower in the morning and rises through the day. The best strategy is to exit avalanche terrain early during warm, sunny days or avoid it during rainy days. Monitor how well the snow surface refroze overnight, and time your descent so that you are riding in a couple inches of supportive corn skiing, rather than punchy, trap-door snow or ankle deep slushy snow. Look for evidence of recent wet avalanches on similar slopes to clue you in to dangerous conditions. Monitor mountain temperatures from these weather stations and expect cloudy nights to prevent a better refreeze.
-Cornice Falls
Springtime is the season that large cornices that have been growing all season begin to weaken and fall. These can also be triggers for slab avalanches. Cornices tend to break wider than expected. Give cornices a wide berth if you are traveling along a corniced ridgeline, and limit your amount of exposure climbing underneath cornices, especially during the peak of warming.
The CBAC will continue to monitor the snowpack and post updates to our website and our facebook page if conditions warrant. The CAIC will issue statewide updates on Mondays, Wednesdays, and Fridays into the spring season.
Spring Travel Advisory 2015
Issued 4/6/15 by CBAC
Spring season is a great time of the year to get into the mountains and generally offers better stability and more manageable avalanche problems for backcountry travelers. However, avalanches conditions can still be dangerous during spring, and there are several kinds of problems you should continue to monitor and assess in you springtime adventures.
-Storm instabilities
Spring snowfall will usually fall on some form of crust. These surfaces do immediately bond well. Anytime a slab of new or windblown snow forms, expect touchy conditions during and shortly after the storm. New snow becomes especially sensitive as the sun comes out immediately after the storm and quickly consolidates into more of a storm slab. Expect leeward and crossloaded features at higher elevations to hold thicker and more sensitive windslabs following a storm with moderate or strong winds. These kinds of instabilities are generally short-lived during the springtime, but can last for several days after the storm on shaded aspects or higher elevations. The best strategy is to monitor how much snow accumulates during a storm and ease into small and manageable terrain until you’ve assessed how large and how sensitive new slabs are. Be wary of windloaded slopes and avoid heavily windloaded features following a significant storm. The Schofield Pass SNOTEL, which is northwest of town, and the Butte SNOTEL, which is on Mt. Crested Butte, are local remote snow sensors that update hourly. Storm or wind slabs are most problematic over consequential terrain with cliffs, gullies, long vertical, or rocks and trees.
-Wet avalanches
When the sun (or rain) comes out after a spring storm and moistens the new snow, loose wet avalanches become frequent on any slope steeper than 35 degrees, and these point releases typically fan out and entrain all of the new snow down to previous crust layers. These are usually small and predictable, but can carry significant mass after a large storm or in terrain with significant vertical relief. They can also gouge deeper and grow larger entraining the full snowpack during prolonged warm-ups. Wet slabs can be a larger and more dangerous problem. These are caused by liquid water percolating to and compromising the strength of buried weak layers. This year, our snowpack is about a month ahead of schedule, meaning our April avalanche problems are more typical of May problems. Most slopes facing east through south through west, as well as lower elevations that face north, have seen water run through the entire snowpack and have already been delivered the dry to wet “spring shock”. These slopes saw a wet avalanche cycle in mid-March. A number of these slopes have matured into a stable, spring snowpack, but it is difficult to identify which ones could still be harboring the threat of a wet slab. Northerly facing slopes near and above treeline have seen less, if any, meltwater, and still primed for wet slab activity when temperatures and the higher sun angle turn on the water factory. Last year, these slopes began their wet slab cycle around late May to early June. The size of wet slabs failing on deeply buried weak layers will be likely be large at these elevations. Wet slabs are most likely to occur during prolonged warm-ups and/or following multiple nights without a good refreeze. If we see a dust-on-snow event, this will expedite surface warming. Wet avalanche danger is usually lower in the morning and rises through the day. The best strategy is to exit avalanche terrain early during warm, sunny days or avoid it during rainy days. Monitor how well the snow surface refroze overnight, and time your descent so that you are riding in a couple inches of supportive corn skiing, rather than punchy, trap-door snow or ankle deep slushy snow. Look for evidence of recent wet avalanches on similar slopes to clue you in to dangerous conditions. Monitor mountain temperatures from these weather stations and expect cloudy nights to prevent a better refreeze.
-Cornice Falls
Springtime is the season that large cornices that have been growing all season begin to weaken and fall. These can also be triggers for slab avalanches. Cornices tend to break wider than expected. Give cornices a wide berth if you are traveling along a corniced ridgeline, and limit your amount of exposure climbing underneath cornices, especially during the peak of warming.
The CBAC will continue to monitor the snowpack and post updates to our website and our facebook page if conditions warrant. The CAIC will issue statewide updates on Mondays, Wednesdays, and Fridays into the spring season.