In order to ski "the steep and the deep" you are no longer trying to identify unstable slopes so you can avoid them, you are trying to find stable ones so you can ski them.

While we can take some comfort from the statement made by avalanche guru Ed LaChapelle that "the snow is stable 90% of the time", there will always be risk when skiing steep slopes in the backcountry.

How can you reduce the risk to an acceptable minimum while still enjoying a good days' skiing?

If you are a serious deep powder hound you will learn to distinguish the good days from the bad, to observe current snow conditions, to evaluate snow stability from a few simple tests, to recognize signs of instability and, perhaps the most important factor in reducing the odds, you will practice safe skiing techniques.

Some Important Considerations
Many of the tip and techniques described in this chapter have already been covered in the chapters on "Observing Snow Conditions" "Recognizing Avalanche Terrain" and "Hazard Evaluation". Although I will cover some of the points again, you should review these chapters for applicable material and refer to the chapter on "Observing Snow Conditions" for a description of the tests for snow stability.

Risk
A discussion on evaluating snow stability would not be complete without some mention of risk. In the introduction I state that "Only by recognizing risk can you use your knowledge and experience to reduce that risk". It can be further argued that whatever your personal acceptable level of risk the potential reward must always outweigh the risk. In other words don't stick your neck out for a run or two of lousy skiing. Save all of your "nine lives" (hopefully more) for those occasional perfect days.

Everyone has a different tolerance for risk, from the risk-seeker who skis steep slopes regardless of conditions to the person with a low tolerance for risk who will only venture onto steeper slopes when the snowpack is indisputably stable.

When skiing with a large group or with companions who are better skiers, you should avoid being pressured into accepting more risk than you really want to tolerate. Be aware of your companions' attitude to risk and make adjustments on the conservative side if necessary.

Skiing Companions
Your choice of skiing companions is an important factor in the pursuit of safe skiing. The riskier the skiing the more critical it is to know their skiing ability and experience, their tolerance for risk and their potential behaviour in an emergency. Ideally you should ski with a small group of companions of similar ability and with similar tolerance for risk. If you ski with a large group you will have to be much more conservative in your choice of slope as it is much more difficult to apply the principles of safe skiing to a big group.

The ideal group size is one which is small enough to be manageable and large enough to be effective in the event of an avalanche rescue. Four is a good number. Skiing alone leaves no margin for error and is not a good idea in avalanche terrain.

Ability
Because a good skier making smooth turns stresses a slope much less than a falling skier, you should match your skiing ability with the steepness and stability of the slopes you ski. A skier who has a tendency to "crash and burn" on steep slopes should not ski steep powder of dubious stability. There are some experts who consider that to ski deep powder in marginal conditions you should be able to "parallel" ski, as "telemarking" puts a greater stress on the snow!

Before You Go

Safety Equipment
It is probably stating the obvious to point out that if you are a deep-powder fanatic you should possess, carry and know how to use basic safety and rescue equipment. If you get into trouble, self rescue is your only hope. Make sure that all your party have working avalanche beacons and are proficient in their use.

Local Knowledge
Your margin of safety will be much higher if you ski slopes you know well, than if you ski a new area. If you ski regularly in the same area over a period of years you will learn which slopes can be safely skied in different snow conditions and which slopes are prone to avalanching. You will get a feel for the area so that your observations of conditions will become keener. The importance of local knowledge cannot be overstated.

Form an Opinion on Snow Stability
If you are skiing in your local area and have followed the build-up of the snowpack and recent changes in weather you should be able to form an opinion, no matter how rough, about current snow stability. Build up an overall picture as the winter progresses and revise and refine this picture every time you go skiing. Choose your destination for the day with this picture in mind, and as you approach your chosen slopes compare your stability prediction with actual snow conditions. Do not let your desire to ski a slope interfere with your evaluation of its stability

Snow, Avalanche and Weather Reports
In many areas you can obtain up-to-date avalanche forecasts prepared by professional forecasters. While these reports are usually for large regions or even for whole mountain areas, in times of high or extreme instability they will sound a warning bell. They will often indicate the conditions which are causing instability such as persistent buried surface hoar or wind loaded slopes of a certain aspect. Along with a call to the weather office a call to your nearest avalanche forecast centre or to park rangers and wardens is one of the prerequisites for safe skiing.

Wait for the Right Conditions
Successful (surviving) extreme skiers make meticulous preparations and wait for exactly the right conditions before making their descent. Following their example, you should wait for the right conditions before skiing a particular slope or gully. Be flexible in your choice of slopes; if conditions are not right go somewhere else. Timing is everything!

Snowcraft
Snowcraft is a little used term for an almost lost art. Anchorage avalanche educator, Doug Fesler, calls it "wearing your avalanche eyeballs." Like navigation it is the art of observing, storing and compiling into a picture a multitude of minute details. Observation is the key to safe travel through avalanche terrain and a major factor in evaluating the stability of a snow slope.

Look for recent avalanche activity, settling of the snowpack or cracks in the surface due to settlement. Feel the snow with your skis to detect any changes to hardness or texture. If you are following in the tracks of other skiers, step out of the trail occasionally. If there is fresh snow, check the depth as you ascend and evaluate how well it is bonded to the old snow surface. Look for signs of drifting. What has been the direction of the wind recently? Keep you eyes open and your senses alert. Gather as much information as you can.

A good guide depends largely on "feel". The "feel" of the snow beneath his skis as he turns and a "sense" of terrain. His built-in wealth of experience attunes him to anticipate potential problems as he skis various types of terrain just as a good driver senses potentially dangerous situations developing around him on the highway.

Weather
Don't forget to observe the weather. Changes in weather, particularly heavy snowfall, current wind speed and direction or a sudden rise in temperature all have an important effect on snow stability.

Test Slopes
Small, steep slopes along your route will give some indication of stability. Try to ski them off or jump on the top of them. Jump on cornices as long as you can do it safely. A good sized chunk of cornice rolling down a slope without triggering a slide will give you a lot of confidence in a slope's stability.

Ski cutting the top of large slopes is a much dicier business and should be done with caution. Never ski cut below a cornice. A snowboarder became the first snowboard avalanche fatality in Canada by doing this.

Snowpits
Dig a snowpit on a test slope in a safe location. It is usually not necessary for the backcountry skier to dig more than about 1.5 - 2 m deep. You really have no way of evaluating deep instability and if deep instability is forecast by your local avalanche warning centre you should be skiing somewhere else; somewhere safe.

According to Bruce Tremper, a professional stability forecaster, "The name of the game is to dig a pit in the most representative spot you can choose without getting killed". You may have to settle for a smaller test slope, and try to extrapolate the results to the larger slope, or work your way in towards the middle of the larger slope, digging several quick pits and retreating if there is any indication of instability.

In order to get reliable results, take care when choosing your snowpit locations. Stay away from trees; avoid drifts or ridges where the wind may have altered the layering of the snowpack; be aware of rockbands, buried bush or other shallow spots and avoid breaks or transitions in the slope. The ideal location is in the middle of a steep, open slope!

As you dig, pay attention to the consistency of the snow. You can learn a lot about the composition of the snowpack during the digging process.

Feel the snow with your gloved hand to get an idea what layers are present in the snowpack. Don't bother with brushes or credit cards or with looking at the snow crystals with a magnifying glass. All you are trying to see is the overall picture. Look for the weakest layer and try to estimate how well it is bonded to the adjacent layers.

Shovel Shear Test
Do a Shovel Shear test looking for weak layers, especially layers of buried surface hoar. Remember that the shovel shear test is a good way to identify weak layers in the snowpack but a poor way to evaluate its stability. Review the procedure on page 103 and make sure you know how to do it correctly. The way you cut the back of the column is critical.

Loaded Column Test
Do a Loaded Column test to identify the weakest layer and to get an idea of how much weight can be applied to the snow before it fails.

Rutschblock Test
Do a Rutschblock test as a practical evaluation of stability and as a means of filling in your snowpit as a courtesy to other skiers.

If you find no significant instability work your way out onto the edge of the slope you wish to ski, probing with ski poles as you go to determine if the consistency of the snow and the makeup of the layers remains the same. Do another quick series of tests. Depending on what you find you may wish to stick your nose farther out onto the slope, or you may decide to retreat

Procedure for Stability Evaluation

• Form an opinion on current stability from your home.
• Call the avalanche hotline for your area.
• Pick the area in which to go skiing based on the above opinion.
• Observe slopes visible from the road as you drive to your destination.
• Decide the slope you are going to ski when you get to the area and have had a chance to evaluate stability.
• Determine the angle of your intended slope. Is it 35° or steeper?
• Practice the fundamentals of snowcraft.
• Jump on small, steep test slopes along the route to see if they slide.
• Jump on cornices as long as you can do it safely.
• Dig a snowpit pit on a test slope in a safe location.
• Pay attention to snow consistency as you dig.
• Run a gloved hand down the pit wall to get an idea of layering.
• Look for the weakest layers.
• Do a Shovel Shear test to identify weak layers.
• Do a Loaded Column test to identify the weakest layer and to estimate how much weight can be applied to the snow before it fails.
• Do a Rutschblock test as a practical evaluation of stability.
• Probe with ski poles as you climb to the top of your chosen slope to determine if the consistency of the snow and the makeup of the layers remains the same.
• If in doubt do another quick series of tests.
• Practice "Safe Skiing" techniques.

Safe Skiing

`The first rule of thumb in safe skiing is, if your partner wants to ski first ...let him!" Brad Meiklejohn

After stability evaluation the best way of "Reducing the Odds" is to practice safe skiing techniques. There is one overriding rule for safe skiing and that is; never expose more than one skier at a time to avalanche danger. The following are pointers gathered from ski guides, avalanche professionals, extreme skiers and backcountry ski fanatics.

One thing all these people have in common is that they are willing to turn around and go home if they become uncomfortable about the level of risk.

Managing your party

• Plan your descent. Decide where on the slope you will put the first track, who will ski first, which side of the first track the second skier will ski and how far down the slope you will ski before stopping to regroup. Stop at the very edge of the slope or ski right to the bottom.
• If the entire run is not visible, stop (to the side) at any changes in steepness or direction and ski the new section as a separate slope.
• Ski one at a time and watch each skier for the entire run. Don't start until the previous skier is out of the way. Skiing one at a time keeps the stress on a slope to a minimum.
• Don't ski above one another. Take care when tree skiing or skiing rolls and bumps not to ski above you partner. Move well to one side or to a safe position following your run.
• Use the buddy system and stay within sight or sound of your buddy at all times

Skiing the slope

• Start the day by skiing easier angled slopes and work your way onto the steeper slopes. Ski treed slopes before open ones.
• Typically the first run of the day is always a safe run with several test locations for stability evaluations; a small steep roll or short commonly wind-loaded slope. Continue to sniff around, being constantly aware of changing weather and snow conditions.
• Start skiing a slope at the sides, working towards the centre on successive runs.
• Ski on ridges instead of bowls; stay out of gullies and avoid skiing slopes which channel into gullies; be alert for terrain traps.
• Enter the slope at the top rather than at the sides. Don't ski in from the side below a cornice.
• Take a good look at the slope and consider the possibility of "weak spots". Ski where the snowpack appears to be deepest, avoiding possible "weak spots" In depth hoar conditions stay away from rocks which may be trigger points.
• Ski as smoothly as possible and in control. Sit down rather than crash.
• Ski the same slopes as often as you can throughout the season. This not only gives you an intimate knowledge of the terrain, but also ski packs the snow, reducing its potential for sliding.
• Put your climbing track on safe, low-angled slopes. Climbing straight up on foot should only be done on the most stable slopes.
• A new lesson learned from heli-skiing is to look well above and contemplate triggering an avalanche that starts a long distance away.

Weak Spots

It is possible that, on any given slope, the strength of a buried weak layer, or of the snowpack itself, may vary from place to place.

Consider a slope covered with a certain depth of snow. If the slope were perfectly even , you would expect the snowpack to be uniform across the slope. However, if the slope is uneven or if there are buried rocks or brush, then the temperature gradient in those areas will be different and the snowpack will no longer be uniform. In climates where recrystallization is taking place such areas may be weaker and potentially less stable due to the higher rate of recrystallization. These areas are called "weak spots"

In studying a number of slab avalanches which have been triggered by a person adding stress to a weak layer, it has been noticed that the initial rupture of the slab usually begins in a localized area where the weak layer is at its weakest.

Once failure occurs at the "weak spot", the fracture propagates rapidly throughout the slab into areas of stronger snow; into snow which your companions may have safely descended.

The Implications of "Weak Spots"

The farther down the weak layer is in the snowpack, the less likely you are to trigger an avalanche, therefore you should try to ski where the snow cover is deepest and keep away from rocks or brush protruding from the snow. On suspect slopes, follow the exact line taken by the person in front.

Remember that the more you concentrate your weight in a small area the more stress you transmit to the snowpack. A snowboarder will add less stress to a weak layer than will a person on skis. Taking your skis off and walking down a slope is a dubious technique when slab conditions are suspected.

The old concept of moving between "islands of safety" needs revising to stress that the "islands" should be large and solid. A substantial clump of trees or a solid rock buttress, rather than insubstantial objects such as small trees or brush sticking up through the snow.