Hazards 2

Avalanches

The avalanche is the most underestimated danger in the mountains. People generally think that they will be able to recognize the hazards and survive being caught. The truth is a somewhat different story. Every year, 120 - 150 people die in small avalanches in the Alps alone. The vast majority are reasonably experienced male skiers aged 20-35 but also include ski instructors and guides.[citation needed] There is always a lot of pressure to risk a snow crossing. Turning back takes a lot of extra time and effort, supreme leadership, and most importantly there seldom is an avalanche to prove the right decision was made. Making the decision to turn around is especially hard if others are crossing the slope, but any next person could become the trigger.

There are many types of avalanche, but two types are of the most concern:

1. The slab avalanche: This type of avalanche occurs when a plate of snow breaks loose and starts sliding down; these are the largest and most dangerous.
1. Hard slab avalanche - formed by hard-packed snow in a cohesive slab. The slab will not break up easily as it slides down the hill, resulting in large blocks tumbling down the mountain.
2. Soft slab avalanche - formed again by a cohesive layer of snow bonded together, the slab tends to break up more easily.
2. The loose snow avalanche: This type of avalanche is triggered by a small amount of moving snow that accumulates into a big slide. Also known as a "wet slide or point release" avalanche. This type of avalanche is deceptively dangerous as it can still knock a climber or skier off their feet and bury them, or sweep them over a cliff into a terrain trap.

Dangerous slides are most likely to occur on the same slopes preferred by many skiers: long and wide open, few trees or large rocks, 30 to 45 degrees of angle, large load of fresh snow, soon after a big storm, on a slope 'lee to the storm'. Solar radiation can trigger slides as well. These will typically be a point release or wet slough type of avalanche. The added weight of the wet slide can trigger a slab avalanche. Ninety percent of reported victims are caught in avalanches triggered by themselves or others in their group.

When going off-piste or traveling in alpine terrain, parties are advised to always carry:

1. avalanche beacon
2. probe
3. shovel (retrieving victims with a shovel instead of your hands is five times faster)

and to have had avalanche training! Paradoxically, expert skiers who have avalanche training make up a large percentage of avalanche fatalities; perhaps because they are the ones more likely to ski in areas prone to avalanches, and certainly because most people do not practice enough with their equipment to be truly fast and efficient rescuers.

Even with proper rescue equipment and training, there is a one-in-five chance of dying if caught in a significant avalanche, and only a 50/50 chance of being found alive if buried more than a few minutes. The best solution is to learn how to avoid risky conditions.

Ice slopes

For travel on slopes consisting of ice or hard snow, crampons are a standard part of a mountaineer's equipment. While step-cutting can sometimes be used on snow slopes of moderate angle, this can be a slow and tiring process, which does not provide the higher security of crampons. However, in soft snow or powder, crampons are easily hampered by balling of snow which reduce their effectiveness. In either case, an ice axe not only assists with balance but provides the climber with the possibility of self-arrest in case of a slip or fall. On a true ice slope however, an ice axe is rarely able to effect a self-arrest. As an additional safety precaution on steep ice slopes, the climbing rope is attached to ice screws buried into the ice.

True ice slopes are rare in Europe, though common in mountains located in the tropics, where newly-fallen snow quickly thaws on the surface and becomes sodden below, so that the next night's frost turns the whole mass into a sheet of semi-solid ice.

Snow slopes

Snow slopes are very common, and usually easy to ascend. At the foot of a snow or ice slope is generally a big crevasse, called a bergschrund, where the final slope of the mountain rises from a snow-field or glacier. Such bergschrunds are generally too wide to be stepped across, and must be crossed by a snow bridge, which needs careful testing and a painstaking use of the rope. A steep snow slope in bad condition may be dangerous, as the whole body of snow may start as an avalanche. Such slopes are less dangerous if ascended directly than obliquely, for an oblique or horizontal track cuts them across and facilitates movement of the mass. New snow lying on ice is especially dangerous. Experience is needed for deciding on the advisability of advancing over snow in doubtful condition. Snow on rocks is usually rotten unless it is thick; snow on snow is likely to be sound. A day or two of fine weather will usually bring new snow into sound condition. Snow cannot lie at a very steep angle, though it often deceives the eye as to its slope. Snow slopes seldom exceed 40°. Ice slopes may be much steeper. Snow slopes in early morning are usually hard and safe, but the same in the afternoon are quite soft and possibly dangerous; hence the advantage of an early start.

Crevasses

Crevasses are the slits or deep chasms formed in the substance of a glacier as it passes over an uneven bed. They may be open or hidden. In the lower part of a glacier the crevasses are open. Above the snow-line they are frequently hidden by arched-over accumulations of winter snow. The detection of hidden crevasses requires care and experience. After a fresh fall of snow they can only be detected by sounding with the pole of the ice axe, or by looking to right and left where the open extension of a partially hidden crevasse may be obvious. The safeguard against accident is the rope, and no one should ever cross a snow-covered glacier unless roped to one, or even better to two companions. Anyone venturing onto crevasses should be trained in crevasse rescue.

Weather

The primary dangers caused by bad weather centre around the changes it causes in snow and rock conditions, making movement suddenly much more arduous and hazardous than under normal circumstances.

Whiteouts make it difficult to retrace a route while rain may prevent taking the easiest line only determined as such under dry conditions. In a storm the mountaineer who uses a compass for guidance has a great advantage over a merely empirical observer. In large snow-fields it is, of course, easier to go wrong than on rocks, but intelligence and experience are the best guides in safely navigating objective hazards.

Summer thunderstorms may produce intense lightning. If a climber happens to be standing on or near the summit, they risk being struck. There are many cases where people have been struck by lightning while climbing mountains. In most mountainous regions, local storms develop by late morning and early afternoon. Many climbers will get an "alpine start"; that is before or by first light so as to be on the way down when storms are intensifying in activity and lightning and other weather hazards are a distinct threat to safety.

Altitude

Rapid ascent can lead to altitude sickness. The best treatment is to descend immediately. The climber's motto at high altitude is "climb high, sleep low", referring to the regimen of climbing higher to acclimatize but returning to lower elevation to sleep. In the South American Andes, the chewing of coca leaves has been traditionally used to treat altitude sickness symptoms.

Common symptoms of altitude sickness include severe headache, sleep problems, nausea, lack of appetite, lethargy and body ache. Mountain sickness may progress to HACE (High Altitude Cerebral Edema) and HAPE (High Altitude Pulmonary Edema), both of which can be fatal within 24 hours.

In high mountains, atmospheric pressure is lower and this means that less oxygen is available to breathe. This is the underlying cause of altitude sickness. Everyone needs to acclimatize, even exceptional mountaineers that have been to high altitude before. Generally speaking, mountaineers start using bottled oxygen when they climb above 7,000 m. Exceptional mountaineers have climbed 8000-metre peaks (including Everest) without oxygen, almost always with a carefully planned program of acclimatization.

In 2005, researcher and mountaineer John Semple established that above-average ozone concentrations on the Tibetan plateau may pose an additional risk to climbers.

Hazards

The craft of climbing has been developed to avoid three main types of danger: the danger of things falling on the climber (objective danger), the danger of the climber falling and inclement weather. The things that may fall include rocks, ice, snow, other climbers or their gear; the mountaineer may fall from rocks, ice or snow, or into a crevasse. In all, there are eight chief dangers: ,falling rocks, falling ice, snow-avalanches, falls,the climber falling falls from ice slopes, falls down snow slopes, falls into crevasses and dangers from weather. To select and follow a route using one's skills and experience to mitigate these dangers is to exercise the climber's craft.

Falling rocks

Every rock mountain is slowly disintegrating due to erosion, the process being especially rapid above the snow-line. Rock faces are constantly swept by falling stones, which are generally possible to dodge. Falling rocks tend to form furrows in a mountain face, and these furrows (couloirs) have to be ascended with caution, their sides often being safe when the middle is stoneswept. Rocks fall more frequently on some days than on others, according to the recent weather. Ice formed during the night may temporarily bind rocks to the face but warmth of the day or direct sun exposure may easily dislodge these rocks. Local experience is a valuable help on determining typical rockfall on such routes.

The direction of the dip of rock strata often determines the degree of danger on a particular face; the character of the rock must also be considered. Where stones fall frequently debris will be found below, whilst on snow slopes falling stones cut furrows visible from a great distance. In planning an ascent of a new peak mountaineers must look for such traces. When falling stones get mixed in considerable quantity with slushy snow or water a mud avalanche is formed (common in the Himalaya). It is vital to avoid camping in their possible line of fall.

Falling ice

The places where ice may fall can always be determined beforehand. It falls in the broken parts of glaciers (seracs) and from overhanging cornices formed on the crests of narrow ridges. Large icicles are often formed on steep rock faces, and these fall frequently in fine weather following cold and stormy days. They have to be avoided like falling stones. Seracs are slow in formation, and slow in arriving (by glacier motion) at a condition of unstable equilibrium. They generally fall in or just after the hottest part of the day, and their debris seldom goes far. A skillful and experienced ice-man will usually devise a safe route through a most intricate ice-fall, but such places should be avoided in the afternoon of a hot day. Hanging glaciers (i.e. glaciers perched on steep slopes) often discharge themselves over steep rock-faces, the snout breaking off at intervals. They can always be detected by their debris below. Their track should be avoided.

Falls from rocks

The skill of a rock climber is shown by one's choice of handhold and foothold, and his adhesion to those one has chosen. Much depends on a correct estimate of the firmness of the rock where weight is to be thrown upon it. Many loose rocks are quite firm enough to bear a person's weight, but experience is needed to know which can be trusted, and skill is required in transferring the weight to them without jerking. On rotten rocks the rope must be handled with special care, lest it should start loose stones on to the heads of those below. Similar care must be given to handholds and footholds, for the same reason. When a horizontal traverse has to be made across very difficult rocks, a dangerous situation may arise unless at both ends of the traverse there be firm positions. Mutual assistance on hard rocks takes all manner of forms: two, or even three, people climbing on one another's shoulders, or using an ice axe propped up by others for a foothold. The great principle is that of co-operation, all the members of the party climbing with reference to the others, and not as independent units; each when moving must know what the climber in front and the one behind are doing. After bad weather steep rocks are often found covered with a veneer of ice (verglas), which may even render them inaccessible. Crampons are useful on such occasions.

Technique on Mountaineering

Snow

While certain compacted snow conditions allow mountaineers to progress on foot, typically some form of mechanical device is required to travel efficiently over snow & ice. Crampons are device having 10-12 spikes which are attached to a mountaineers boots, are used on hard snow (neve) and ice to provide additional traction & allow very steep ascents and descents. There are many different varieties, ranging from lightweight aluminum models intended for walking on glaciers to aggressive steel models intended for vertical and overhanging ice and rock. Snowshoes can be used to walk through deep snow approaching the mountain or on lesser slopes up the mountain. Skis can be used almost everywhere snowshoes can and also in steeper, more alpine landscapes although it takes more practice to develop sufficiently strong skiing skills for difficult terrain. The practice of combining the techniques of alpine skiing and mountaineering to ascend and descend a mountain is a form of the sport by itself, called Ski Mountaineering. Ascending and descending a snow slope involves many different techniques of the feet and an ice axe which have been developed over the last hundred years, originating in Europe. The progression of footwork from the lowest angle slopes to the steepest terrain is first to splay the feet to a rising traverse, to kick stepping, to front pointing the crampons. The progression of the ice axe technique from the lowest angle slopes to the steepest terrain is to use the ice axe first as a walking stick, then a stake, then to use the front pick as a dagger below the shoulders or above, and finally to swing the pick into the slope over the head. This also involves different designs of ice axe depending on the terrain to be covered, and even whether a mountaineer uses one or two ice axes.

Glaciers

When traveling over glaciers, crevasses pose a grave danger. These giant cracks in the ice are not always visible as snow can be blown and freeze over the top to make a snowbridge. At times snowbridges can be as thin as a few inches. Climbers use a system of ropes to protect themselves from such hazards. Basic gear for glacier travel includes crampons and ice axes. Teams of two to five climbers tie into a rope equally spaced. If a climber begins to fall the other members of the team perform a self-arrest to stop the fall. The other members of the team enact a crevasse rescue to pull the fallen climber from the crevasse.

Ice

Multiple methods are used to safely travel over ice. If the terrain is steep but not vertical, then protection in the form of pickets or ice screws can be driven into the snow or ice and attached to the rope by the lead climber. Each climber on the team must clip past the anchor, and the last climber picks up the picket. This allows for safety should the entire team be taken off their feet. This technique is known as Simul-climbing.

If the terrain becomes vertical then standard ice climbing techniques are used.