 |
 |
|
|
|
January, 2007
Riding Shotgun Down the Avalanche...Or Not!
By Jon Tierney
I'm riding shotgun down the avalanche
Tumbling and falling down the avalanche
So be quiet tonight the stars
shine bright
On this mountain of new fallen snow ....
Lyrics from song by S. Colvin - J. Leventhal
Whumpf! Crack! These are the sounds most dreaded by winter backcountry users. Snow packs are schizophrenic - displaying periods of quiet, soft beauty amidst violent and unforgiving displays of natural power.
Avalanches are the bane of backcountry travelers and they don’t care if you are skier, snowboarder, snowshoer, or snowmobiler. In fact, in the past ten years snowmobilers have outpaced backcountry skiers by over 2:1 for avalanche fatalities nationwide. And yes, avalanches happen in the east. Almost every year people are hurt or killed by avalanches in New England and Quebec. Some unknowingly charge blindly into the mountain’s gunbarrel not even aware of the risks while the skeptics stay at home waiting for the ideal that may never come. In reality, the mountain snowpack is stable most of the time. The trick is to recognize the situations when it’s not. Armed with some education and wise preparation, one is able to travel with a reasonable degree of safety most of the time.
The New England snowpack is an anomaly for scientists sharing characteristics of a warmer maritime snowpack coupled with often-artic temperatures. Record the weather for two weeks and you will understand its complexity. On Monday it’s snowing and 15 degrees - 11" of pow, wow, it’s gonna be good. Tuesday, the wind is up to 90 mph on the summit of Mount Washington. By Wednesday, it’s drizzling rain and 30. Then into the deep freeze on Friday with temperatures plummeting to well below zero. Can you say consistently inconsistent?
Without getting too much into the dynamics of snow ...
The slab avalanche is the most dangerous type of avalanche in New England. It’s commonly formed by wind scouring the snow as it hits a mountain and then depositing the snow on the other side. This deposition is what gives us great spring skiing on Mount Washington but during the early and midwinter it can create a layer of bonded snow sitting on top of a bunch of ball bearings or on a thin layer of ice on top of soft snow. The problem with slabs is that they can appear firm and often are. However, firmness can be deceiving. Consider a 6" layer of firm Styrofoam suspended between two cinderblocks. A cat walks across it without a hitch while a person’s weight shatters it. It’s all a matter of strength vs. stress! Imagine the woes an engineer would face if she had to use metal building material that consistently existed within 50 degrees of it’s melting point! That is the nature of snow and why predicting avalanches is as much art as science.
Here are some general guidelines that will help you avoid being pummeled.
Weather Red Flags
>30 cm of new snow
>3 cm/hour of snow fall
>Winds capable of transporting snow
>Temperatures near or above freezing (0? C/32? F)
>Any rapid changes in temperature
>Rain/dense snow
>Strong sunlight directly onto snowpack
Terrain Red Flags
>30? - 45? slopes
>Leeward, wind-loaded slopes
>Trigger Points: Convexities, isolated trees, rock, snow pillows
Snowpack Red Flags
>Shallow snow <1.5m deep
>Presence of facets anywhere in the snowpack
>Layer and spatial variability
Avalanche Activity Red Flags
Are avalanches occurring on similar aspects at the time you want to travel?
These represent very elemental considerations. Before traveling in avalanche terrain take a course with an experienced professional. Learning from friends just doesn’t usually give you the whole picture. Learn as much as you can about avoiding avalanches through terrain recognition, weather interpretation, snowpack assessment, route finding, travel techniques and field rescue skills. The time to learn this is before you need it. I see so many students taking a course because they had a near miss and scared themselves.
One of the most important aspects of avalanche avoidance is preparation and route planning. Resist the urge to get in the car and head for the new POW. A few minutes planning ahead will start you asking the right questions and thinking about alternatives. Think about the terrain you want to go to - its aspect, angle, wind/sun exposure. What are your ideal plans and safer plans? What are your route options? Who are your partners? Do they have similar goals? How would you characterize the risk profile of your group? What are their skills? Do you have the necessary gear? Food? Water? Clothes?
Okay, so you are out there getting ready to rip it up. Will you be ascending your intended descent route or not. On an ascent, your exposure time will be much greater but you usually have more time to look around whereas on a descent you have less exposure but things are happening much faster. Here are some tips for traveling more safely in avalanche terrain:
* Travel during the best times of day when the snow is stable
* Stay high in start zones or avoid them
* Reduce the number of people exposed by moving one at a time through hazard areas
* Watch each other and listen for whumpfs (sorry, you have to take those earphones off)
* Communicate: Know where you and everyone else are going
* Move fast from safe area to safe area
* Avoid trigger points such as convexities, small trees and rocks
* Take breaks and adjust the pace to the weakest member
* Have releasable bindings on your skis or board
Be sure to carry avalanche rescue tools and know how to use them. As a minimum this means a transceiver, probe, and shovel plus first aid kit, extra clothes, etc. A shovel or probe is of no use to you if you are buried with it so make sure everyone in the group is equipped. A lot of people skip the probe thinking the transceiver will get you close enough. The beacon gets you close, the probe hits the bulls eye. That probe can cut off a couple minutes of digging time. Trust me, if you are underneath, that’s an eternity and can mean the difference between being a vegetable or not.
Beyond owning gear, learn to use it well and continually practice. Stay up to date with technology - it’s getting easier every year. Recently I had an experienced skier take a course to refresh his skills. Only a few days after his course he was involved in an avalanche that caught 11 out of 14 people on a guided backcountry ski trip in Canada. Boy, was he glad for the time and money he had just spent doing beacon drills and rescue sled work. And this accident just reinforces the fact that avalanches happen even to full-time guides who train and work in the snow year after year. While professional guides can better assess and reduce travel risks, they can’t eliminate them. That’s just part of the definition of adventure.
Finally, try a little patience. The snow pack is always seeking stability. Usually a few days time is enough to allow the snow to settle and the old snow to adjust to the additional weight or stressors either by settling or releasing.
Mountain travel is far safer than driving an automobile on America’s roads, but if you spend a lifetime in the mountains there’s a good chance that something will happen to you. And you should be ready for this. Remember that it can happen to you! Mountains are long-term residents, you can always come back next week and they will be just as beautiful.
[side bar]
Avalanche Hazard Scale
The hazard scale is available in forecasted areas. It is a piece of additional information to add to your avalanche information pile.
Low: Human triggered avalanches are unlikely. Very small likelihood of burial.
Moderate: MOST PEOPLE ARE CAUGHT UNDER MODERATE CONDITIONS.
Human triggered avalanches are possible. Potential for burial is there especially in terrain traps. Exercise cautious travel techniques.
Considerable: Human triggered avalanches are probable with increased potential for burial. Avoid terrain red flags.
High: Human triggers are certain with potential for large burials
Extreme: Widespread, large scale avalanche activity occurring. Find something else to do.
[Side bar] Tips for Choosing an Avalanche Course Provider
* Look for an AIARE or AAA sanctioned course. These courses, particularly AIARE, have a lot of curriculum support, flow sequentially from one to the next, and have an instructor training program.
* Evaluate the instructor’s experience guiding and skiing / climbing in different snowpacks - big mountain, continental, maritime, New England, South America, Europe, etc.
* Evaluate the instructor’s teaching ability. It doesn’t matter how much experience they have if they are not good at organizing a course, staying focused and communicating.
* Make sure they have gear - transceivers, etc. especially if you don’t have one.
* Some providers also offer gear discounts for course participants.
Jon Tierney is an internationally licensed IFMGA mountain guide and paramedic. He has been guiding and instructing ice and rock climbing , ski mountaineering, wilderness medicine and outdoor leadership since the early 1980s. He is also a lead instructor for Wilderness Medical Associates. Jon currently owns Acadia Mountain Guides Climbing School and Alpenglow Adventure Sports in Orono and Bar Harbor.
Email nick [at] noumbrella [dot] com with your questions, comments and concerns.
Design and Content © 2002 to 2006 No Umbrella
