If you're an outdoors person who thinks a snow avalanche is a rather semi-comic idea found only in hackneyed movies and Bugs Bunny cartoons, consider this real-life diary submission from a man hiking in Nepal:

Friday, 10 November. Ang Tsering and I ask all to pack essentials in their day packs for possible bailout if this [snow] continues. We meet in the dining tent (resurrected). I hear Ang Tsering yell "avalanche!" and the next thing I know I'm doubled over -- pinned against the table. We all get out OK, and we're clearly blessed. The table either saved us or the avalanche had run its course.

Three of our tents were eight feet deep and five people would have been buried had they still been packing. Three tents and the dining tent were totally trashed. Most people were now without duffels, sleeping bags or day packs. We decided to get the hell out and return to dig out our tents when this stopped.

About ten minutes down the trail, the route looked suicidal. Below us in a narrow valley, a group was trying to dig a trail. In 30 minutes, we moved about 50 feet. Visibility was 200 feet, snowing in sheets, and we could hear but not see avalanches booming on all sides. This was a doomsday scenario; there we were, standing in this mess without food, clothing or sleeping bags. We went back and built a snow platform behind a safe rock.

We'll take a quick look at the necessary conditions for an avalanche, then study how you can survive such a happening - or even avoid it altogether - during your romp in the snow.

Avalanche Conditions

"Lean snow winters are often dangerous avalanche winters. That's because the thin snow cover in November and December turns to weak sugar snow. When heavier snow falls in late December and in January, that's when the problems begin. The snowpack becomes the classic house of cards, with a layer of slab snow sitting on top of the sugar snow. The slightest disturbance can bring it down," says Knox Williams, director of Colorado Avalanche Information Center (CAIC).

Williams insists the keys to fewer avalanche deaths are education and prudence, especially when people visit deep, rural regions.

Doesn't technology find and save most of those caught in an avalanche? "Yes and no," says Williams. "Yes, because avalanche beacons have saved several lives the last few years by allowing a buried victim to be found quickly; but also no, because once a person is caught in an avalanche, luck may play a larger role in survival than rescue equipment. Less than half of the people with beacons who are buried by an avalanche actually survive. That's because a beacon cannot save you if you are severely injured or buried deeply.

"Wouldn't it be better to not get buried at all?" Williams continues. "The key to survival is avoiding accidents altogether through knowledge and good decision-making in the backcountry."

Well, how serious is the threat of an avalanche anyway? How worried should you be?

Because snow avalanches are really a whole season's snow released down a mountainside at once, an avalanche may release tremendous forces and are a serious threat to the winter traveler.

If you like skiing or snow-related activity, it is very important that you learn how to avoid being in an avalanche, and increase your chances of survival if you find yourself in one.

There are literally a ton of factors that can contribute to avalanche conditions. The possible combinations of factors are endless, and the forecasting of a possible avalanche will often require the evaluation of extremely complicated situations. However, there are many practical things you'll read about here that can be helpful to you.

It's important: both experience and statistics show that fully-buried avalanche victims who are still alive when the avalanche stops moving must usually be found and dug out within 15 minutes to have any reasonable chances of survival. To tell the truth, in North America the chances of an organized professional rescue team arriving in that time frame are pretty slim unless the accident happens in an area where an avalanche safety program operates. But even in such areas, alerting a team and quickly mounting an organized rescue may well take longer than the 15-minute window of opportunity.

Therefore the efforts of those who survive or witness an accident (often called 'self rescue techniques' by those in the know) are absolutely crucial to the survival of any victims. If those on the scene fail to at least locate any buried victims, it is unlikely that the organized rescue teams will arrive in time to make a live recovery.

So the makeshift locating and possible rescue procedures should be understood and practiced by those planning a few days in a winter wonderland, in order for the event of an avalanche self rescue to truly be fast and efficient.

Every situation has some rules all its own, but these general guidelines should give you a good footing (no pun intended) when you're trying to cope with the fallout (pun here is intended) of an ugly avalanche.

Factors of Terrain

*Slope steepness - Slopes of 30-45 degrees are the ones most likely to avalanche, but anything in the neighborhood of 25-60 degrees can do so under certain conditions.

*Slope profile - Convex slopes are clearly the most dangerous; stay away from them when you can, especially during the period from late December thru January. Concave slopes are less dangerous, but they can - and sometimes do - avalanche.

*Slope aspect - North-facing slopes are the most likely to avalanche during the dreaded middle of winter. But south-facing slopes can become dangerous in the spring and during sunny days, as the sun begins to rise higher in the sky.

Also, slopes that garner snow during windy conditions are dangerous because wind-borne snow adds to their rapid accumulation; the hard, hollow-sounding wind slab may develop there. However windward slopes (those slopes sitting into the wind) generally have less snow and benefit from wind compaction.

*Ground cover - Areas with large rocks, trees and heavy brush here and there are a good help in anchoring the snow on the mountain. Smooth, grassy slopes are much more dangerous.

What about Snow?

*New Snow - You should especially suspect dangerous conditions with a foot or more of soft, new snow. However, conditions can always be hairy. Stay on your guard whenever you're around snow-covered mountain regions.

Rapid snow settlement is actually a favorable sign. Look for settlement cones around tree trunks and over rocks. Moist, dense precipitations create those sought-after settlement cones, because the snowfall settles rapidly.

Lack of settlement is a danger sign; loose, dry snows avalanche easily. During windy periods all bets are off however, as even these snows can suddenly become very dangerous.

*Old Snow - When the old snow depth is sufficient to cover natural anchors, such as rocks and brush, additional snow layers will slide more readily. Also, the nature of the old snow surface is important. Rough surfaces are of course favorable for stability; any smooth surfaces, such as sun crusts, are not.

A loose, underlying snow layer is more dangerous than a compacted one. You can check this with a ski pole, ski, or snowshoe.

Ever wonder why you see those pro skiers banging the ends of their poles into a deep snow before beginning a day of skiing? Now you know.

*Crystal Types - All snow is not created equal. You can readily observe general crystal types by letting them fall on a dark ski mitt or parka sleeve. Small crystals, such as needles and pellets, result in more dangerous conditions than the usual star-shaped crystals.

The Weather

*Wind - Sustained winds of 15 m.p.h. and over during a storm cause trouble fast. Snow plumes from ridges and peaks indicate that wayward snow is being blown onto these slopes during clear weather and that dangerous conditions may be developing, even though it is not storming.

*Temperature - Snow persists in an unstable condition longer under cold temperatures. It settles and stabilizes more rapidly during warmer weather that's near or above freezing.

But beware high and rapidly rising temperatures in the spring months. They may result in wet snow slides, particularly from south- facing slopes.

*Beware of any rapid change in temperature. Shadows creeping across a slope may change temperatures enough to create dangerous conditions.

*Snowfall Rate - Snow falling at the rate of one inch per hour or more increases avalanche danger rapidly.

General Observations

*Old Slide Paths - An avalanche path that has slid once will slide again. Look for old scars in timber and avoid steep gullies and steep, open slopes.

*Recent Avalanche Activity - Look around; if you see new avalanches you should suspect dangerous conditions.

*Sound and Cracks - If the snow sounds hollow, particularly on a slope full of wind-blown snow, conditions are probably dangerous; if the snow covers cracks that are found running in the snow, slab avalanche danger is high.

Information

Check weather forecasts. For particular information, contact a US Forest Service Snow Ranger or the nearest winter sports area ski patrol.

Route Selection

*The safest routes are on ridge tops and slightly on the windward side away from the ridges' edge.

*Windward slopes are almost always the safest.

*If you cannot travel on ridges, the next safest route is out in the valley away from the bottom part of slopes.

*Stay high and near the top if you must cross dangerous slopes or avalanche paths; if you can see old or new avalanche fracture lines, be sure to avoid them and other similar areas.

*Go straight up or down if you must ascend or descend a dangerous slope; do not make traverses back and forth across it.

*Take advantage of areas of dense timber, ridges or rocky outcrops as islands of safety. Use them for lunch and rest stops and spend the least time possible out on the open slopes.

*Snowmobiles must not travel across the lower part of slopes, and especially not across long, open slopes or known avalanche paths.

*Look for, and obey, all signs or other warnings of avalanche danger.

Avalanche Precaution - Rules of Thumb

*Only one person at a time on a suspect slope: all others watch the person that may be in danger.

*Remove ski pole straps and ski safety straps; loosen all equipment, put on and fasten mitts, cap, and all other clothing before being exposed to avalanche danger.

*Carry and use an avalanche cord, as well as a sectional probe.

If Caught in an Avalanche:

*Discard all equipment (skis, poles, snowboard, snowshoes). If you have a snowmobile, leave it.

*Remember the terrain. Be prepared for falls over cliffs, collisions with trees, and the stop in the runout zone.

*Seek shelter behind rocks, trees, vehicles.

*Crouch low and turn away from the avalanche.

*Cover nose and mouth.

*Brace against impact, hold onto trees, etc.

*Do not cry out or open your mouth as the avalanche is occurring.

As the avalanche slows:

*Pull hands and arms to the face and make an air space.

*Thrust and kick to the surface just before the snow comes to a complete stop.

*Try to stay on top and work your way to the side of the avalanche.

*Thrust an arm toward the surface.

When the avalanche has stopped:

*Try to dig yourself out.

*Call out when you can, especially when rescuers are near.

*Though we're sure it will be close to impossible, try to stay calm. The most important thing you can have at that moment is a clear head. Use it.

If you are the Survivor:

*Mark the place where you last saw the victims.

*Search for them in the fall line and directly below the last seen point.

*Search the area of greatest snow deposition first.

You are their best hope for survival. Do not desert those trapped and go for help unless you are certain help is only a few minutes away.

Remember, you must consider not only the time for you go to get help, but the time required for help to return. Also, the victim has only a 50% chance of surviving for an hour.

If you do go for help, mark the route so a rescue party can follow it back.

Now if you are in a vehicle, the first thing to do is turn off the engine. Do not smoke or use matches. While it may not be obvious at first, these activities will waste what precious air you have - a definite no-no.

Open a window and check for depth of burial with some kind of stick, pole or probe. Do not leave the vehicle unless you feel sure it is safe to do so or you are in a remote location.

If you have a two-way radio, keep it turned on; it may quickly become your best friend in this situation. Use it to call for help.

Search & Rescue

The two very best ways to initialize a good rescue if you happen to survive, witness, or come upon an avalanche accident are:

1.) To make sure at least one of you possesses and can work an avalanche transceiver, which helps you find those lost in the snow, and;

2.) To always travel and work in a group when you are traversing the snowy realms.

A number of years ago all manufacturers of avalanche transceivers agreed to manufacture only transceivers that transmitted and received on a frequency of 457 kiloHertz (or 457 kHz). One of the benefits of using this frequency is that it allowed a new and faster searching method, called the "induction-line" technique, to be employed. Up until that time transceiver searches were conducted using an older and usually much slower technique called the "grid-search technique." This simple improvement has saved many a life.

Learning the induction-line technique is a practical skill and it should be practiced several times a season or, better still, at the beginning of each outing. Like most techniques, this procedure cannot be learned from a simple description alone.

In addition, at the beginning of each trip and at critical points thereafter, avalanche transceivers should be checked periodically to ensure the device is in working order.

The basis of the induction-line technique utilizes the fact that an avalanche transceiver actually has an electromagnetic field that surrounds it each time the transceiver transmits. This field has a three-dimensional shape somewhat like an apple, surrounding the device and whoever is using it at that moment.

Using the transceiver in 'receive' mode, the searcher moves or orients their transceiver until it is passing along one of the "flux lines" of the electromagnetic field. That "flux line" is then followed like a railroad track curving into a station (naturally the flux lines are not actually visible, but you are in effect following an induction-line or flux line - hence the name of the technique).

Once you have picked up a signal, you begin by carefully scanning to find the direction in which the signal is strongest. You now quickly move in that direction for a distance of about 15 feet - that's 5 meters to the world outside the US. If the signal immediately gets weaker, consider moving in the opposite direction instead. You always want to travel in the direction that makes the signal stronger or sound louder. On beacons with visual indicators, you want more lights or bars illuminated on an LED or LCD display.

Some points to keep in mind when pinpointing:

*Particularly if using transceivers with loudspeakers, only one person should home in and pinpoint the signal.

*When homing in on the victims location, move as quickly as possible and turn the volume of your transceiver down whenever possible.

*When pinpointing the final location, use a logical pattern and slow down so as not to miss the strongest point.

*Mark the area where the signal is strongest.

*Probe the marked area using a logical pattern.

*When the victim is hit with the probe, do not remove the probe. Notify the rescue leader of the hit. Note the approximate depth of the victim. Begin rescue digging.

Victim Recovery and Rescue Digging

Digging for a victim is tiring and can take actually longer than the search, so it is important to be as efficient as possible. Here are some tips that make the recovery process easier and faster.

If the victim is deeply buried, begin digging well away from the probe. As a rule of thumb, the hole required to expose the victim will be at least the square of the depth: that is, if a victim is buried 6 feet deep (or 2 meters), the hole required to remove the victim will be at least 6 feet by 6 feet.

Dig on the downhill side of the probe and throw snow downhill.

Too many people digging at once get in each others' way. It's a better idea to use only a few diggers at one time. Besides, diggers should be rotated often anyway - every few minutes if possible. As soon as one begins to tire or slow down someone fresh should take over. There's no room for ego here. Time is absolutely of the essence.

Deep holes may require tiers with diggers on each tier moving snow from the bottom to the surface.

When the victim is found, uncover the head and chest immediately, clear the mouth and airway, and begin first aid while the rest of the victim's body is still covered.

If a transceiver search is unsuccessful, secondary procedures - such as setting up a probe line - must be used.

Setting Up a Probe Line

If a transceiver search is unsuccessful, probe around likely burial areas; for example, around found articles belonging to the victim(s), around trees, rocks, in gullies or deep deposits. Basically anywhere known or suspected to be the victim's line of travel.

Make sure to mark recently probed areas. With every second counting, you don't need to look over the same real estate twice.

If probing around found items or in likely areas of burial is unsuccessful, an organized probe line may be useful if there are enough searchers on the scene to set one up. A probe line needs at least 6 searchers to be efficient. If there are not enough searchers, continue with the probing of likely areas.

Recent Research (Auger and Jamieson, 1997) indicates that the "three hole per step" technique is the most efficient means of probing and can be effective even with relatively small numbers of probers.

To set up the probe line, establish the most likely area of burial. Line up searchers in a straight line and space them apart approximately from wrist to wrist. Searchers probe three times: once directly in front of them, then reaching left and right with their probe about 1 1/2 feet (or about 45 cm) on either side of the middle hole. Searchers take one normal step forward and repeat the process.

As noted above, the '3 hole per step technique' has distinct advantages, particularly where a small group of rescuers must search a large area. It has been widely adopted throughout many areas as one of the quickest, easiest ways to find someone trapped under an avalanche quickly.

The Open Space Coarse Probe

On particularly rough terrain or when fewer rescuers are available, probers spread out from fingertip to fingertip. Each prober then inserts their probe once just outside of the left foot, then again just outside of the right foot. This technique provides much of the efficiency as the '3 hole' technique, but the speed with which the area is covered diminishes.

Probing for a Vehicle When searching for vehicles a probe spacing of 4 feet (120 cm) is used. Two steps forward are taken between each probe insertion to maintain this spacing.

The Fine Probe

As noted above, the '3 hole per step' technique has distinct advantages, particularly where a small group of rescuers must search a large area. But when a protracted time has passed without success (many hours or even days) and the rescue team leader feels there's very little hope of finding a buried avalanche victim alive, an alternative probing technique may sometimes be employed. The "fine probe" technique has a very high probability of detection (near 100%). Due to the fact that it uses a much closer spacing, the amount of time and manpower required to search a given area is greater and can take as much as five times as long to probe a given area as with the '3 hole per step' method.

Self Rescue on Roads

Carrying out a self rescue where an avalanche-covered road strewn with vehicles may be involved will follow a similar procedure to that described above. There are some specific considerations, however:

*Stop in a safe location.

*Direct vehicles and people to a safe area.

*Check dimensions of avalanche and determine whether vehicles could be caught in it.

*Before carrying out any rescue procedures, carefully assess the potential for further avalanches. (Remember, you do not have as much information as you might in a backcountry situation.)

*If you feel the situation is unsafe and that no one is buried in the avalanche, simply send for help and wait for assistance.

Getting Help

Which brings us to the last real issue: getting help. If help is nearby, consider the safety of those going out, how many will be left to continue searching, the probable time before rescue teams arrive, and the survival chances of any victim(s) during that time.

Also, before going for help note the following information:

*the exact location of the accident;

*access (road, trail, helicopter);

*time of accident;

*weather and snow conditions;

*if number of people buried, how many;

*rescuers on site

Continue searching for as long as you can, but make provisions for the feeding, sheltering, and safety of searchers if an extended hunt is anticipated.

As we've said at the beginning of this article, no descriptions can prepare you for every eventuality; but we feel we've given you a fighting chance. Remember, even experienced mountain climbers like the ones trekking thru Nepal at the beginning of this little composition discovered what can happen in an instant during an avalanche.

Also, if it weren't for the watchful eyes of the man who wrote that Nepalese diary entry and his associate, many of their friends might still be lost in the mountains of Nepal if they hadn't been on the lookout, and if all those involved hadn't worked together thru the whole ordeal. That, dear friends, is probably the most important avalanche lesson we can give.