Mountain Backstroking

Winter's back and so is the Avalanche Hazard. Time to smarten up.
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Winter's back and so is the Avalanche Hazard. Time to smarten up.

Ahhh, the return of winter! Suddenly it's cold and snowy throughout much of the United States. Even Dallas, Seattle and Las Vegas got dumped on. That's welcome news for most of the drought-ridden West, along with skiers, snowshoers and snowboarders coast to coast. It also means the usual spate of early season avalanche deaths as snow-starved fun seekers find the creamy drifts irresistable.

Last Saturday a skier was caught in the Chugach Range near Anchorage. The next day skiers died in Colorado and Utah. On Wednesday, a ski patroller at Mammoth Mountain, California was caught and partially buried (not uncommon for patrollers doing 'ski cuts' to evaluate hazardous slopes). For each of those incidents I guarantee there were at least 10 to 20 close calls that went unreported.

Avalanches don't form a common risk for most wilderness adventurers, but for winter recreationists in any steep terrain they are a major hazard. Last year, 33 skiers, snowboarders, snowshoers, snowmobilers died in U.S. avalanches, the highest recorded annual fatality rate. Some of this had to do with autumns that nowadays (post-1986 in Utah) often start with one big October dump followed by a month or two of no precipitation and cold temperatures. This creates a ground layer of sugary snow called 'depth hoar' that's loose, uncolidated and prone to collapse. Once big snowfalls finally arrive, all those tons of weight rest atop the depth hoar like pianos on ball bearings. This dangerous underlayer can remain for months.

Avalanche science can be complex, and it's always a good idea to take an avalanche course if you're a winter sports enthusiast who regular ventures on or below tilted slopes. However, many avalanche courses obsess on geeky scientific stuff about layering, snow physics and digging pits to evaluate stability. As a former avalanche instructor I'm tempted to dive into all that, but while this info is useful for professionals who issue warnings or protect ski areas and mountain roads, for most outdoor travelers the true key to safety is not crystallography and pit-digging, it's safe traveling policy.

In fact, most avalanche victims are experienced skiers and boarders who've taken avalanche classes, have a basic understanding of snow science, and are carrying shovels and beacons. Unfortunately, they also think this knowledge and equipment allows them to tweak the rules and walk a finer line of risk. Not so. (The reason? Your data is never complete, because the snow slope is not rigged with sensors.)

An admission of guilt here: The above perfectly describes me between the years of 1975 and 1990, during which I was caught in six avalanches. Most of them weren't a surprise. I was an experienced powderhound who knew I was pushing it. Fortunately, I was never injured or completely buried. Some of that was choosing my 'fights', but most of it was dumb luck.

So for readers who want to head into the hills to enjoy winter, but are worried about avalanches, perhaps even frightened off by them, I offer the bullet points below, along with some links for further study. If readers are interested in having me do a more detailed series on avalanche dynamics and avoidance, request it in the comments section.

AVALANCHE FACTS

[] Avalanches don't leap at you like a predator. Virtually all backcountry incidents result from avalanches triggered by the victim or one of their party. Don't mess with hazardous slopes and they won't mess with you.

[] Avalanches usually occur on slopes between 30 and 55 degrees in angle, so stay off slopes that steep, and well away from the 'run-out zone' below them, and you'll be safe in most winter conditions.

[] Most avalanches happen during or shortly after snowstorms, because the snow hasn't had enough time to flow and settle, releasing stresses gradually. Instead, those stresses release suddenly, as an avalanche. Most dangerous slopes don't release on their own. The slopes that 'hang fire' are the problem.

[] Wind greatly increases avalanche hazard by piling snow deeply on leeward slopes (perhaps four times as fast and deep as straight-down snowfall rates) and mechanically packing it into slabs that can weigh thousands of tons and hold stresses for long periods.

[] Discontinuous weather creates distinct layers within the snowpack. Often this includes icy layers that are perfect sliding surfaces, weak layers that are prone to collapse, and cohesive slabs that form the 'punch' of a dangerous avalanche.

[] Avalanche slopes don't have to be big to be dangerous. Typical backcountry snow weighs between 200 pounds (fluff) and 500 pounds (floury) per cubic meter. So even small slides can bury you beneath tons of snow, especially if you're in a gully where debris will pile deeply. That weight can also smash you against trees and rocks, twist your limbs like a rag doll, and make digging you out a slow proposition. If you are buried you will not be able to move.

[] Most avalanche victims die of asphyxiation. When snow slides and settles, it becomes dense and hard, shutting off oxygen. If you can breathe, exhaled breath will quickly form an ice mask around your face.

[] According to one study of 422 buried victims, your chance of survival is 92% if you are found and dug up within 15 minutes. After 35 minutes, survival rate drops to 37% and plummets rapidly after that. It takes an experienced, practiced group to find and dig up a victim in that time frame, especially in steep, awkward terrain.

[] About 20% of avalanche fatalities die from injuries received during the slide, not asphyxiation. So an army of beacon-armed shovelers is still no guarantee. If all the gear and buddies make you plunge more confidently into risky situations, that is a false sense of security.

[] Many avalanche texts talk about how to fight the avalanche, keep swimming, and cover your mouth as it rolls to a stop. This is potentially useful but largely fatuous advice. Chances are you'll be tumbled uncontrollably and end up injured, buried, with your mouth packed full of snow.

The upshot: Avoid getting caught. The rest is secondary.

SO, BEFORE YOU GO

[] Learn the recent weather and snowpack history. If there's a big ice crust underlying all that new snow, you need to know that.

[] Call the local avalanche forecast center, if one is in your area.

[] Talk to others who have been out. Outdoor shops and clubs are often a good source of beta.

[] On the way to trailhead, and often during your tour, keep reevaluating the conditions. If they're different than what you expected, ditch your preconceived notions and maybe change plans. Don't get stubborn.

[] Take a shovel, avalanche beacon, and emergency gear, and the practice to use them properly, but realize that these are second lines of defense. If you don't own the gear, you can still go out, but you've got to smarten up, stay alert, and travel cautiously.

ON YOUR TOUR

[] Realize that even on 'low hazard' days, there will be dangerous pockets (steep gullies, beneath cornices, etc).

[] If you're hiking on gentle terrain and the snow keeps settling around you with audible 'whumps,' avoid any inclined slopes and give them a wide berth when traveling beneath. This is the sound of collapsing snow layers. All they need is a slope, and you've got an avalanche. However, the lack of collapses doesn't mean it's safe.

[] Use your shovel to dig a few snow pits down to ground level and see the layers for yourself. But don't use pits to determine whether your desired slope is safe or not. To know that, you'd have to dig right in the middle of the suspect slope. A pit dug on ridgeline tells you little about conditions in the gully below. Pits are for general evaluation, not spot predictions.

[] Remember that good weather and/or big groups make people overconfident. Avalanche hazard still exists on sunny bluebird days, and you can die in a party of 12.

[] Ridgelines, flat open valleys, dense timber, and wind-scoured slopes are the safest routes of travel.

[] Deep leeward snow 'pillows,' gullies, and convex slopes that roll over onto steeper terrain are typical avalanche traps.

[] If you must cross a potential avalanche slope, proceed one at a time between islands of safe terrain. Maintain your spacing and watch your partners whenever they're at risk. There is no excuse for multiple victims. Be aware that groups of people tend to huddle close for conversation, or a sense of security when the weather's bad - Not good.

[] If an avalanche does go off, and a member of your party is caught and buried, YOU are the rescue team. You and your party should do everything possible to find and dig them out immediately. Unless you've got a large group and can send individuals, going for help means a body recovery.

[] Rad photos and jaw-dropping ski movies lead to much stupid behavior. Life is not a Warren Miller flick or Black Diamond catalog. There is real danger underlying all that adventure glamor, but it rarely ends up in the layout or footage.

FURTHER RESOURCES

[] Avalanche.org: The portal for most North American avalanche information centers.

[] Utah Avalanche Center: Their daily bulletins, extensive weather analysis, and photo-filled incident reports are an excellent learning source regardless of your home location.

[] ABC's of Avalanche Safety, by Sue Ferguson and Ed LaChapelle. An excellent pocket guide to touring safely.

[] Staying Alive in Avalanche Terrain, by Bruce Tremper. A superb and comprehensive guide. Probably the best single book out there.

[] Snow Sense: A Guide to Evaluating Snow Avalanche Hazard, by Jill Fredson and Doug Fesler. Another excellent book, but with more of an emphasis on meteorology and snow physics.

[] Secrets of the Snow: Visual Clues to Avalanche and Ski Conditions, by Ed LaChapelle. Like a birder's identification guide - to snow slopes and the hazards they may contain.