Tips To Keep You Beeping

                  With the arrival of some real snowfall and wintery conditions, the ski conditions have drastically improved.   But with the new snow came plenty of avalanches in the backcountry around Crested Butte.  If you are just now digging out your winter sticks and brushing the dust off your beacon, here is some recent news and important reminders about avalanche beacons.

                  John Barkhausen of Prescott College recently published his research about whether electronic devices interfere with avalanche beacons.  You’ve probably heard rumors that having your phone turned on could affect your beacon’s performance.  John tested this by systematically checking the effective searching range of a beacon and with different electronic devices turned on, such as cell phones, iPods, GPS units, radios, SPOT locators, and digital cameras.  The good news is that these devices have very little effect on a sending beacon (i.e. the buried victim’s beacon).  The bad news is that a number of electronics significantly reduce the ability of a searching beacon to pick up a signal.  IPod’s and cameras were especially bad.  However, when a searching beacon is held more than 40 cm away from the various devices tested, interference is essentially gone.  This is about arms length away.   So the bottom line is hold your beacon away from your body if you have any electronic devices on.  It’s probably a good idea to turn off your cell phone and reconsider using a chest-mounted GoPro.  If you’re listening to your IPod, then you probably didn’t hear the rumbling collapse that would have warned you of dangerous avalanche conditions in the first place.

                  Another recent study in Europe showed that novice/average users failed to find the last burial victim in a triple burial scenario in roughly 30% of rescue scenarios.  This was attributed to failure of the marking function that most modern beacons are equipped with.  While multiple-burial marking functions are a great addition to beacons and can save precious time, it is important to remember that they are not fail proof.  The bottom line is that you need to practice backup search strategies too.  For more information about these techniques, check out http://beaconreviews.com/transceivers/multipleburials.asp  If beacon searches are a foreign skill to you, check out one of the many avalanche classes offered in the valley.

                  And lastly, some friendly reminders.  Don’t use rechargeable batteries or lithium batteries in your beacon; they could cause unexpected loss of power while you’re out in the backcountry.  Make sure to change your batteries when they get near 50% power; lower power can reduce effective search ranges.  Make beacon checking part of your daily routine, and most importantly, Practice! Practice! Practice! 

Zach Guy

What is "CONSIDERABLE" danger?

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This past week’s never-ending storm cycles has renewed the promise of a deep and snowy winter in the Elk Mountains. Hopefully, most skiers and riders got to surf their powder boards and slake their thirst for the cold smoke. If you were in the backcountry, your endeavors for epic faceshots were likely punctuated with some boot shaking signs of instability in the snowpack. Aside from wondering why you still don’t have real health insurance, your recent experiences might have brought you to ponder the details of the Avalanche Danger Scale. That’s what I did, anyway.

When was the last time that you read the Danger Scale? I mean, really read it. I know, it sounds silly. Green is “Go” red is “Go home,” right? As you look deeper it’s a lot more nuanced than that. It may surprise some backcountry enthusiast to know that the forecasters at the Crested Butte Avalanche Center read the Danger Scale almost every morning. There are days when we may spend fifteen minutes mulling over the specifics of a danger rating before issuing a forecast. This might seem like a trivial thing for a forecaster to do rather than performing some kind of crepuscular snow-ritual deep in the mountains. This attests to the importance we place on the danger rating. Which bring us to the point of Considerable Danger.

Starting December 9^th the Crested Butte Avalanche Center saw the most prolonged period of Considerable avalanche danger so far this season. Sure it’s early, but this period lasted well into late December. Backcountry travelers who were out during this time will recognize that conditions during in this period varied greatly. So, why all the Considerable? This is the beauty and flexibility of this danger rating.

First, some basic criteria would say that “dangerous avalanche conditions” exist under a Considerable rating, and “careful snowpack evaluation, cautious route-finding and conservative decision-making” are essential to staying safe. Though there may be some inherent risk to backcountry skiing and riding, it’s not often that it’s “dangerous.” During times of Considerable danger you really have to be on your game.  The conventional way of thinking about Considerable would tell us that “natural avalanches are possible” and “human triggered avalanches are likely.” This isn’t a time for that romantic picnic lunch you’ve been planning in the middle of your favorite avalanche path. We know that during Considerable danger there’s a good chance we’ll see some kind of avalanches. We want to minimize the amount of time that we’re in any avalanche paths to ensure that we’re not caught in any of them. This is where things get interesting. According to the size and distribution definition, during Considerable danger we could see “small avalanches in many areas, large avalanches in specific areas, or very large avalanches in isolated areas.” In case there’s some confusion with the terms, a large avalanche is something you definitely don’t want to be caught in. This could be big enough to break trees or bury a car. Meanwhile, a “small avalanche” could still be big enough to bury a person. “Specific terrain” could be something like east aspects, while “isolated terrain” could be a 40-degree convex slope containing large rocks. The size and distribution helps explain how different types of conditions can fall under Considerable. Additionally, forecasters strive to match the conditions with a danger that best describes it as a whole.  The overall conditions and size and distribution are just as important to consider as whether we expect natural versus human triggered avalanches. Unfortunately, backcountry riders don’t get to choose which flavor of Considerable they want, but the forecaster often emphasizes the most pertinent elements of a given day’s Considerable.  This helps explain why during mid-December we had so many days that were Considerable. Some days we expected human triggered slides and maybe some naturals, but we new they would be small. Other days we didn’t think there would be lots of activity, but we knew anything that ran it could be big. Some days were really heads up with many small avalanches everywhere and a few large slides on specific slopes.

Most important is to recognize that days with Considerable danger are significantly more hazardous than days at Moderate. Forecasters consider the Danger Scale to be exponential, rather than a linear scale. One step up on the Danger scale could mean that you’re 10 times, or even 100 times more likely to trigger an avalanche. There are lots of times when we can get great powder in the backcountry and even shred some pretty steep slopes. It’s critical that we learn to recognize when it isn’t safe and how to modify our terrain choices to not get caught in dangerous conditions.  If you take some time to review the danger scale, you’ll start noticing how much the CBAC forecasters incorporate the definitions into the daily forecast. Like most readers, the CBAC forecasters are excited for a powder-filled winter. We dream of endless fresh tracks, but most importantly we strive to keep our community safe while enjoying the backcountry.

So what is going to happen when it actually snows???

This article will be published in this week's Crested Butte News.

By John MacKinnon

CBAC Forecaster

The long-range weather models are beginning to show those dark red and purple bulls’ eyes of precipitation stacking up over Colorado in the coming week. This is great news because it means winter is finally on its way to Crested Butte; but it is also important to remember that any significant snowfall will bring a return to dangerous avalanche conditions.

Many people are already comparing our delayed start to winter to last year. What both years have in common is a couple of early season storms between late October and mid-November which have been followed by long dry spells. Long dry spells with cold clear nights and mild sunny days have provided the perfect ingredients for our existing snowpack to morph from snow-flakes into large angular snow crystals known as facets. During both years, much of the early season snowpack turned into weak sugary snow during the first part of winter.

So this brings us to the question of what is going to happen when it actually starts snowing. If Monday’s storm (12/3/12) is any proxy for what will happen when we get a significant load of new snow, the results following the upcoming forecasted storms could be impressive. The storm from earlier this week dropped between 1-5” of snow onto our fragile snowpack. As winds pushed this snow around and drifted it on to specific slopes, many small avalanches occurred—most human triggered but some occurred naturally. The weak faceted snow crystals could not support even the smallest of loads.

It is especially important to remember the effects of Monday’s storm if we get a good 12” of snow in the next couple days. If Monday’s storm was akin to throwing a couch cushion onto 50 fluted champagne glasses, imagine what would happen if you began stacking mattresses on those same glasses. Our weak base of old snow would quickly and dramatically fail if loaded with a foot or more of new snow. A mix of patience, caution and respect could be the best tools for dealing with backcountry riding for some time.  

2012-2013 Season Start Up

The Crested Butte Avalanche Center is now open for the 2012-2013 season! While the first year the CBAC was in operation was 2001, this is our 10^th anniversary of becoming “officially” incorporated as a non-profit entity.  Since we opened ten years ago the CBAC had grown into a professional forecasting office with a staff of 4 forecasters and a board of directors of 10 local professionals and backcountry enthusiasts with diverse backgrounds. New this year we will be introducing CBAC Ambassadors who will be the extended face of the CBAC out in the backcountry and here in town as well.

Look for the CBAC to be making some changes to our website product this year. The avalanche forecasting community is making a move to become more consistent with what the avalanche danger means and how to determine what the avalanche problem of the day is. Once the main avalanche problem is determined, it is a bit easier to figure out how to manage the risk for that particular day. Not all avalanche problems are created equal, and not all problems should be dealt with in the same way. Hopefully our new format will make it more evident to backcountry users as to what their considerations for the day should be. Of course we will still have days when our complex snowpack dictates that there is more than just one avalanche problem out there!

While things are slow to get rolling with snowfall in the backcountry so far this year it is important to remember that if there is enough snow to play in, there is also enough to create an avalanche.  While the current avalanche danger is limited to specific areas (where there is actually accumulated snow!) we have already seen some large and impressive slides earlier this month. In your quest to get your season on track, remember to take the time to pay attention to the snowpack. Not just for today’s avalanche conditions, but for what might evolve for the rest of the season. When we get early season snow, and then long dry periods, the snow tends to “rot” or facet. This faceted snow will create a weak layer near the ground, which will be the supporting snow layer for additional snows to (hopefully) come. With a weak supporting structure we can expect to have an active avalanche season! The good news is that with a lot of bare ground showing out there right now, there is no weak base structure yet in some areas. These might be the best places to play in the coming winter.

With not much quality skiing or riding out there just yet, this is a great time to brush up on your avalanche knowledge. The CBAC, in conjunction with Crested Butte Mountain Guides and the Alpineer will be hosting a “Beacon Brush Up” day on Saturday December 1^st. Come on out from 11-3 in the Town Park to learn or practice your beacon skills, demo new avalanche beacons and airbags and get tips from the pros. The Alpineer will host a gathering afterwards from 3-6pm with food and beer as well as special discounts on avalanche gear.

For more information on avalanche danger ratings or avalanche problems, to get the daily avalanche bulletin in the Crested Butte area, to submit your backcountry observations, or to become a sponsor of the Crested Butte Avalanche Center, check out our website www.cbavalanchecenter.org.

What's With All The Scary Danger Ratings?

I'll start off our forecaster's blog with a write-up of the avalanche danger scale and our thought process behind interpreting and assigning avalanche danger ratings this season.

Forecasters around the state have been scratching their heads and  going back and forth about defining and issuing avalanche danger ratings this season. Our tricky snowpack has forced us to dig into the nuances and semantics of the 2010-2011 North American Danger Scale (Fig. 1).

Figure 1

First off, let's get some defintions out there: According to SWAG, avalanche danger, or avalanche hazard, is defined as "the potential for an avalanche to cause damage to something of value [people or property]." A leading authority on avalanche forecasting describes an avalanche danger rating as "a ranking of avalanche danger for a period of time over a specific region." (Stratham et al 2010) 

The CBAC issues an avalanche danger rating of LOW, MODERATE, CONSIDERABLE, HIGH or EXTREME for specific aspects and elevations within our forecast area--the greater Crested Butte backcountry which roughly covers 100 square miles centered around the town of Crested Butte. This creates the Avalanche Danger Rose (Fig. 2):

Figure 2

So what goes into the danger rating? It all starts with the forecasters assessment of snow stability and how the current and future backcountry conditions fit with the avalanche danger definitions. The forecaster looks at the likelihood of both human-triggered and natural avalanches as well as the size and distribution of avalanches. Each level of avalanche danger has a specific definition for those categories (Fig. 1). 

Easy enough, right? If it could only be so simple! It has been very challenging here at the CBAC to attach an avalanche danger rating to our snowpack since the first major storm of 2012 arrived on January 16th. We have been reading (and re-reading) all the qualifying and defining traits of each danger level and assigning danger based on those definitions. Each morning, we look at the probability of both natural and human triggered avalanches and then think about how big avalanches will be and where they will be occurring in the terrain. The resulting product has been a strict interpretation of MODERATE or CONSIDERALE danger that appropriately sums up the avalanche conditions but does not necessarily connote how "dangerous" it is out there. This is where the "SCARY" modifiers have been coming into play this season. 

While not an official danger rating, forecasters often attach or imply the "SCARY" pre-fix during times when the danger is at the upper end of either MODERATE or CONSIDERABLE. Often times during SCARY MODERATE, there is a lower probability of human-triggering an avalanche but the resulting avalanche has the potential to be very large, and deadly. 

We dealt with SCARY CONSIDERABLE after the January 16th storm. 1.3" of water fell on a mostly shallow and weak snowpack. The danger did not spike all the way to HIGH because the size and distribution of avalanche activity did not fully meet the HIGH requirements. We did not see "large avalanches in many areas"-- a clause that helps define HIGH danger. Instead we observed "small avalanches in many areas and large avalanches in specific areas"--two of the defining traits of CONSIDERABLE danger. It was SCARY CONSIDERABLE because we were pushing the limits of the definition, but the way the storm and subsequent avalanche cycle played out fit into CONSIDERABLE danger. During the peak of the storm--the night of 1/16--the probability of human triggered avalanches may have jumped to "Very Likely"--a defining trait of HIGH--but the natural activity observed over the next several days all pointed to the fact it was CONSIDERABLE danger. 

The storm that arrived the following week--the January 22nd storm--dropped over 2" of water onto our weak, top-heavy snowpack. The danger jumped to HIGH post storm due to the combination of a larger load of snow, winds, and our increasingly unstable snowpack. The result of that storm was a spike in danger to HIGH for 24 hours. More larger avalanches were observed after the 1/22 storm than the 1/16 storm and HIGH danger was warranted. 

The danger then hung out at CONSIDERABLE for the next 2 weeks on many aspects. Why? Naturals weren't occurring, but human triggered avalanches were "LIKELY" on most slopes. Going back to the definitions (Fig. 1), "likely" triggers are enough to keep the danger at CONSIDERABLE. Also, all the reports of cracking and collapsing hinted that remote triggered avalanches were a real possibility as were "large avalanches in specific areas and very large avalanches in isolated areas." 

Currently we are at SCARY MODERATE. Human-triggered avalanches are no longer "likely," but they are "possible" and even very possible on certain slopes. Why is the "Scary" pre-fix still being tossed around the forecasting community? We use the term SCARY MODERATE during times when the probability for triggering an avalanche is slowly decreasing, but the consequences remain severe and even deadly. 

The Bottom Line: Our snowpack remains dangerous despite the fact it is getting harder to trigger an avalanche. Don't let decreasing signs of instability lure you into exposed and consequential terrain. Many fatal avalanches or close calls (think Lucky Boy Slide on Whetstone) occur during SCARY MODERATE danger. Do not let your guard down and treat all slopes over 35 degrees with extra caution. 

John MacKinnon

Forecaster

Welcome to the CBAC Forecaster's Blog

Our hope is to provide another forum for spreading information and observations about traveling in the backcountry. Stay tuned for weekly updates. Think Snow!

John