List the main causes of avalanches. How to escape from an avalanche? In avalanche areas

Avalanches. Every year, many people die under them, either because they neglect the danger, or because little is known about avalanches.

Many of us do not take the threat of avalanches seriously until someone is killed or injured in one. The sad fact is that people caught in an avalanche usually provoke them themselves. Skiers cut slopes, climbers go during avalanche times. Moreover, the victims are often professionals in their field, but neglect the avalanche danger. This article provides basic knowledge about avalanches.

Avalanches.

Potential Threats

An avalanche can move at a speed of 200 kilometers per hour. Such a force can smear you against trees and stones, grind you against rocks, make porridge from your insides and pierce you with your own skis or snowboard. About one third of all avalanche victims die due to injuries.

If you have not been injured by an avalanche, you will have to struggle with a mass of snow, the density of concrete, which squeezes your body. The avalanche, which began as snow dust, heats up as it moves downhill from friction on the slope, thaws a little and then freezes tightly around your body. All this mass is enough to squeeze all the air out of your lungs.

If you manage to create an air pocket around you before the snow settles, you have a good chance of surviving. If you and your friends have an avalanche transmitter and know how to use it, then the chances of survival are even greater. However, this is where the race against time begins. Most people are not able to survive under an avalanche for more than 30 minutes (Black Diamond AvaLung backpacks can increase this time to one hour), so it makes sense to buy and learn how to use avalanche transmitters. For lovers of winter freeride, a necessary thing. About 70% of avalanche victims die from suffocation.

The best defense against avalanches is, of course, knowledge of avalanche conditions and slopes, as well as avoiding dangerous situations.

Loose avalanches.

Such avalanches form when there is little or no adhesion to the snow cover. As a rule, such avalanches begin from one point either on the slope surface or close to it. Such avalanches gain a large snow mass and momentum while moving down the slope, often forming a triangular path behind them. The causes of such avalanches may be blocks of snow falling on the slope from the rocks above or melting snow cover.

Such avalanches occur on dry and wet snow, descend both in winter and in summer. Winter loose avalanches usually occur during or after a snowfall. In the warmer season, wet loose avalanches are caused by snow or melt water. These avalanches are dangerous both in winter and in summer.

Plastic avalanches.

These avalanches are much more dangerous. Sheet avalanches form when a single layer of snow slides off the bottom layer and rushes down a slope. Most freeriders get into such avalanches.

They are caused by snowfalls and strong winds that deposit layers of snow that change over time. Some layers are deposited and held together, while others, on the contrary, are weakened. Weak layers are often granular or composed of very light snow (powder) so that other layers cannot adhere to them.

An avalanche occurs when the top layer, called the "board," is not sufficiently bonded to the underlying layer and is set in motion by some external agent, usually a skier or climber. Unlike unconsolidated avalanches, which start from a single point, sheet avalanches grow deeper and wider, usually along a break line at the top of a slope.

Avalanche release on Cheget:

Factors contributing to the descent of avalanches.

Locality.

Slope steepness: pay attention to the steepness of the slope when you ride or climb. Avalanches often occur on slopes steep in 30-45 degrees.

Slope side: in winter, the southern slopes are much more stable than the northern slopes, as the Sun heats and compacts the snow. Unstable layers of "deep frost", dry, icy snow that does not adhere to adjacent layers, are most often found on the northern slopes. Therefore, be careful when you see the tempting northern slope with excellent powder, for they are more dangerous than the southern slopes, due to the fact that they do not receive enough solar heat, which will compact the snow over the winter. At the same time, in spring and summer, the southern slopes melt more strongly, which leads to dangerous wet avalanches. More warm weather at this time of the year it hardens the snow on the northern slopes, making them safer.

Terrain Threats: Snow cover is most often unstable on convex slopes, rock ledges, boulders or trees where the snow cover is interrupted, on lee slopes or under eaves. It is best to bypass bowls, circuses and pits, where snow can accumulate after an avalanche (avalanche discharges). Steep, narrow couloirs (or ravines) usually accumulate a lot of snow and pose a great danger to hikers and skiers caught in them. Often, there is no escape from such places, due to the steep side slopes, so that in the event of an avalanche, there is nowhere to run.

Weather

Precipitation: snow is least stable after snowfalls or rains. A large number of snow that has fallen in a short period of time is a sign of avalanche danger. Heavy snowfall, especially wet or dense snow falling on powder, forms unstable layers in the snowpack. Rain seeps in and heats the bottom layers of the snowpack and also reduces friction between the layers, making them less stable. After a heavy snowfall, you need to wait at least two days before going to avalanche areas.

Wind: Another indicator of snow cover instability is wind. Often strong wind carries surface snow from one slope to another part of the ridge, where the snow descends, forming an avalanche. Pay attention to the intensity and direction of the wind during the day.

Temperature: a large number of problems with snow cover are caused by temperature fluctuations. The formation of snow crystals can change in case of temperature difference between the surface and overlying layers, different layers in the center of the cover, and even between the air temperature and the upper snow layer. A particularly dangerous snow crystal, due to its inability to bond with other crystals, is "hoarfrost".

Deep frost ("sugar snow"), due to its similarity to granulated sugar, can be located at any depth or several depths of deep snow cover. Often a sharp increase in temperature leads to wet avalanches, especially in spring, so be careful when it gets warm in the mountains.

Snow cover

Snowfalls come one after another throughout the winter. Temperature changes cause metamorphoses of snow crystals. If the composition of the snow remains the same, then the snow cover is uniform and stable. Snow becomes dangerous and unstable when layers of different snow form inside the snow cover. To every freerider it is essential to check snow layers for stability, especially on slopes of 30-45 degrees.

How to test a slope for avalanche risk:

Human factor

While terrain, weather, and snow cover play a big role in triggering avalanches, it's important to remember that selfishness, emotions, and herd mentality can seriously cloud your judgment and lead you to make rash decisions. In fact, according to a recent survey of Canadian avalanche workers, respondents indicated ‘human factors’ and ‘ incorrect choice terrain’ as the main causes of accidents caused by avalanches. Most avalanches are caused by humans!

Common mistakes in decision making:

• Familiar places: it is most likely that you will take risks in a place you are familiar with. Conditions, however, can change from minute to minute, so treat any area as if you were seeing it for the first time.
• OK: encouragement from the group can put a lot of pressure on you. "Yes, everything will be fine, relax!". Even if you feel something is wrong, you may be taking unnecessary risks to please the group.
• Reach the place at any cost: if you want too much to get to your destination, you can act contrary to your common sense and ignore the signs of danger, concentrating only on their goals. Foreign climbers call this phenomenon "summit fever".
• "We have an expert": you imply that there is someone else in your group with more experience than you. You think you are, based on the fact that this person was in this place before you or he underwent some kind of special training. Better to ask than to guess.
• Existing trails: you can feel safe because you see a trodden path ahead of you. In our mountains, once I walked along a seemingly excellent path, but I felt that the slope under the path was not very reliable. Just because someone else has been here before you doesn't mean it's safe to walk around.
• "Virgin Fever": You can turn a blind eye to signs of avalanche danger when you have fresh, deep, and untouched snow in front of you. Don't be tempted!
• "Others have passed!": it's very easy to give in to the "herd instinct" and head off onto a dangerous slope when other people have already passed in front of you. Always assess the situation as if you were alone. Tell me if you feel something is wrong.

There are several classifications of avalanches, which are based on different features: the type of snow (loose or dense), the content of water in the snow, the nature of the movement, the sliding surface, and the path morphology.

However, the general classification of avalanches should reflect their most significant features and serve the practical purposes of organizing protection against avalanches. These requirements are best met by two approaches to the division of avalanches into main types. The first genetic - comes from taking into account the causes of avalanches, which were mentioned above; its value lies in the possibility of developing a forecast of the onset of an avalanche danger. The second approach is based on taking into account the relief of the snow-collecting basin and the path of the avalanche. This principle of subdivision of avalanche vehicles makes it possible to calculate the volumes and ranges of avalanche releases, i.e., it is necessary when mapping avalanche-prone areas. In this tutorial, we will consider the first approach to the classification of avalanches.

The genetic classification of avalanches, most fully developed by the Soviet researcher VN Akkuratov, includes the following classes and types of avalanches.

I. Class of dry (cold) avalanches.

Such avalanches usually consist of dry snow; descend mainly in winter; exit paths are not strictly limited - they can go down a flat slope and partially through the air. They have top speed, can form an air wave. The following types of avalanches belong to the dry class:

1. Avalanches from freshly fallen snow. Such avalanches occur due to overloading of slopes during prolonged snowfalls. For avalanches, 0.3-0.5 m of fresh snow is enough. In snowy areas temperate climate this type of avalanches is the main one.

2. Snowstorm avalanches. The reason for their occurrence is high speed growth of the gravity component on the slope. This is the most typical type of avalanche for areas with a moderately cold climate and a stormy wind regime.

3. Avalanches associated with the recrystallization of snow and the formation of layers of deep frost (cohesion forces in which are weakened). Usually rare but powerful avalanches.

4. Avalanches of temperature reduction of snow cover. These avalanches occur as a result of a sharp drop in air temperature. Also a rare type of avalanches.

II. The class of wet (warm) avalanches.

Such avalanches are formed from wet or wet snow; they descend mainly in the spring; exit paths are usually constant; movement is carried out along the lower horizons of snow or on the ground; the speed of movement is less than that of dry avalanches; the impact is mainly due to the pressure of heavy (water-soaked) masses of snow.

1. Avalanches resulting from radiation thaws. These are low-power avalanches of the southern (sunny) slopes.

2. Avalanches associated with thaws and spring snowmelt usually consist of wet, less often wet snow. The sliding surface is usually the interface between snow layers, i.e. avalanches belong to the category of reservoir.

3. Ground avalanches are formed in the spring from wet snow completely saturated with water, due to prolonged thaws and rains, or during rapid snowmelt during dryers. They always descend along certain paths, therefore, as a rule, they have names. They carry a significant amount of detrital material. The roar of these avalanches is called "avalanche thunder" by the inhabitants of the Alps. The most destructive in the class of wet avalanches.

Avalanches are one of the most widespread and dangerous natural phenomena in mountainous countries. Avalanches are mentioned in the writings of ancient writers who lived more than 2000 years ago. The ancient Greek historian Polybius (201-120 BC) writes about losses from avalanches during the passage of Hannibal's troops through the Alps (218 BC). The ancient Roman geographer Strabo (63 BC - 20 AD) wrote about the avalanche danger that awaits the traveler in the Alps and the Caucasus.

In January 1951, the entire Alpine region was in the zone of avalanche disasters. Mountain chain about 700 km long and up to 150 km wide. The snowfall, accompanied by snowstorms, continued in many areas for seven days and ended with a sharp warming. The amount of snowfall in some places exceeded the annual precipitation rate by 2-3 times and reached 2-3 m. The slopes turned out to be overloaded with snow, and mass avalanches began. The entire transport network of the Alps was disrupted - highways and railways were destroyed or blocked in places and temporarily closed. Avalanches descended in places where many generations of inhabitants did not know them. Hotel buildings and protected forests were destroyed. The season was called "Winter of Terror".

In February 1999, an avalanche weighing 170 thousand tons completely destroyed the village of Galtur in Austria, causing the death of 30 people, and in early March 2012, a series of avalanches in Afghanistan destroyed residential buildings, causing the death of at least 100 people.

In Russia, snow avalanches are common in the mountainous regions of the Caucasus, the Urals, in Eastern and Western Siberia, Far East, on Sakhalin.

Today, many countries have accumulated significant experience in avalanche protection.

Complex of anti-avalanche measures consists of two main categories - preventive and engineering.

Preventive actions are reduced to a warning of an avalanche danger and its elimination by artificial dropping. To prevent avalanche danger, maps of avalanche zones and a forecast of the time of avalanches are compiled.

Preventive measures also include warning the population about the onset of avalanche periods.

Artificial dropping of avalanches is carried out by mortars or undermining the avalanche area with explosives. Avalanche collections are also fired for control, in order to check the stability of the snow on the slope.

Engineering measures are usually used to protect settlements and capital structures from avalanches. To do this, tunnels, galleries, sheds are being built. Typically, these structures are used to cover individual sections of railways and highways passing in the mountains.

For many years, structures have been erected that change the path of the avalanche, reduce the speed and range of the release - avalanche cutters, wedges, guide walls, wallpaper dams, etc.

They partially extinguish the energy of the avalanche or divert it from the protected object. Often practiced are such engineering methods as terracing, building slopes with snow-retaining shields. They prevent snow from slipping from avalanches. It's expensive but effective method avalanche control. The protection and restoration of forests on the slopes of the mountains is still considered one of the most important activities in avalanche areas. In the Alps, an avalanche-destroyed forest is immediately restored. The planting of forests is usually combined with the development of slopes with snow-retaining structures.

A dense forest serves as a natural protection against avalanches. It prevents the redistribution of snow by the wind, divides the snow cover into separate sections. In Switzerland, a law prohibiting logging on mountain slopes has existed since the 14th century. The destruction of forests on the slopes of the mountains always stimulates avalanche activity.

Mudflows

Mudflow is a turbulent mud or mud-stone stream, consisting of a mixture of water and rock fragments, which suddenly appears in the basins of small mountain rivers. Mudflows pose a threat settlements, iron and highways and other structures in their path.

The immediate causes of mudflows are showers, intense snowmelt, breakthrough of reservoirs, less often earthquakes, volcanic eruptions.

The tiger in the skin of the lamb called the innocent, at first glance, White snow Matthias Zdarsky is an Austrian researcher who studied the question of what an avalanche is. Softly falling snow captivates even those who dislike winter - it's too beautiful a picture that looks like fairy tale. Yes, and the crystal stars smoothly flying to the ground create a deceptive impression of fragility, defenseless tenderness. However, excessively active snowfalls are fraught with danger, and serious. After all, not only snowdrifts, but also avalanches can grow from small snowflakes. So what is an avalanche? The definition of this concept is given below. And now a little history.

A brief excursion into history

In all likelihood, an avalanche is a phenomenon that has existed as long as the steep slopes of mountains, and Polybius also mentions the first large-scale snowfalls that caused the death of hundreds of people in the context of the history of the campaign of the Carthaginian army through the Alps. And in general, this mountain range, chosen by tourists and climbers, “behind” the longest chronicle of disasters. It is not for nothing that even in the 20th century, masses were celebrated in some areas in memory of those who died under snowy debris, because in this case an avalanche is pain and grief for the relatives and friends of those who suffered from its descent. It is also noteworthy that in one of the last winters of the First World War, more soldiers on the Austro-Italian front died from this than directly during hostilities. And December 16, 1916 went down in history as "Black Thursday", when six thousand people were missing in one day. Hemingway, who was in the Alps at the same time and described his definition of what an avalanche means, noted that winter avalanches are terrible, sudden and bring instant death.

The inhabitants of Norway, Iceland, Bulgaria, the United States, the Russian Federation, Canada, as well as Asian countries: Turkey, Nepal, Iran, Afghanistan, also suffered from the “white death”, and in the latter, the death toll is by and large not kept. Tens of thousands of lives and on the account snow avalanches that fell off Mount Huascaran in Peru.

What is an avalanche? Etymology of the word

The ancient Romans called this phenomenon "a pile of snow." Each nation had its own definition. What does avalanche mean? It's beautiful, exciting and dangerous a natural phenomenon. The very meaning of the word “avalanche” is also interesting, in the origins of which is the Latin root lab, meaning “instability”, although it got into the Russian language through German, since the definition of Lavine existed in Old German. Xuan Zang poetically called them "white dragons", and in the time of Pushkin, avalanches were called avalanches. In the Alps and the Caucasus, the names of individual mountains, gorges and valleys are already "speaking". For example, the Lan forest or Zeygalan Hoch (“mountain from which avalanches always come down”). Sometimes the ability to read onomastics, although it does not tell everything about snow blockages, can save you from unforeseen circumstances.

What is an avalanche

An avalanche is a type of landslide, a significant mass of snow that moves or even falls from the slopes of mountains under the influence of gravity. It simultaneously creates an air wave, which accounts for a significant part of the destruction and damage that is almost inevitable in this natural disaster.

Having started its movement, the avalanche can no longer stop, sinking lower and lower and capturing accompanying stones on its way, ice blocks, branches and uprooted trees, turning from ebullient white snow into a dirty mass, remotely resembling a mudflow. The flow can continue its “fascinating journey” until it stops on gentle sections or at the bottom of the valley.

Factors affecting the convergence of snow masses from the mountains

The reasons causing the convergence of avalanches largely depend on the old snow - its height and density, the state of the surface under it, as well as on the growth of new masses of precipitation. The intensity of snowfalls, subsidence and compaction of the cover and air temperature also affect. In addition, a fairly long open slope (100-500 m) is optimally suited for the start of an avalanche path.

The main "architect" of this natural phenomenon is not in vain called the wind, since an increase of 10-15 cm is enough for the snow to melt. Temperature is also one of the most important factors that can provoke a disaster. Moreover, if at zero degrees the instability of snow, although it arises quickly, but also passes no less actively (it either melts or an avalanche descends). And when the low temperature is stable, the avalanche period increases.

Seismic vibrations can also activate the convergence of snow, which is not uncommon for mountainous areas. IN individual cases there are also enough flights of jet aircraft over dangerous zones.

In general, the increased frequency of snow avalanches is indirectly or directly related to the storm. economic activity a person who is not always intelligent. For example, cut down today woodlands previously served as a natural protection against snow landslides.

Periodicity

Depending on the frequency, intra-annual convergence is distinguished (for winter and spring periods) and the long-term average, which includes, respectively, the total frequency of avalanche formation. There are also systematic avalanches (annually or every 2-3 years) and sporadic ones, occurring a maximum of twice per century, which makes them especially unpredictable.

Movement, the focus of a natural phenomenon

The nature of the movement of snow masses and the structure of the focus determine the following classification: flume snow avalanches, special and jumping. In the case of the first, the snow moves either along the tray or along a certain channel. Special avalanches during movement cover the entire accessible area of ​​​​the area. But with jumpers it’s already more interesting - they are reborn from flume, arising in places of uneven flow. The snow mass has to “jump”, as it were, to overcome certain sections. The latter type is capable of developing the greatest speed, therefore, the danger is very significant.

The snow is treacherous and may well creep up unnoticed and inaudibly, falling in an unexpected shock wave, destroying everything in its path. Features of the movement of these natural masses underlie another division into types. A formation avalanche stands out in it - this is when the movement occurs relative to the snow surface located below, as well as a ground avalanche - it slides directly on the ground.

scale

Depending on the damage caused, avalanches are usually divided into especially dangerous (they are also spontaneous) - the volume of material losses amaze the imagination with their scale, and simply dangerous - they impede the activities of various organizations and threaten the peaceful measured life of settlements.

snow properties

It is also important to note the classification associated with the properties of the snow itself, which is the basis of the avalanche. Allocate dry, wet and wet. The first is characterized high speed convergence and a powerful destructive air wave, and the masses themselves are formed at sufficiently low temperatures after significant snowfalls. A wet avalanche is snow that has chosen to leave the cozy slopes at above freezing temperatures. The speed of movement here is less than in the previous ones, however, the density of the cover is also greater. In addition, the base can freeze, turning into a hard and dangerous layer. For wet avalanches, the raw material is viscous, wet snow, and the mass of each cubic meter is about 400-600 kg, and the speed of movement is 10-20 m / s.

Volumes

Well, the simplest division is small and almost harmless, medium and dangerous to humans, as well as large ones, which on their way wipe buildings and trees from the face of the earth, turn vehicles into a pile of scrap metal.

Can avalanches be predicted?

It is extremely difficult to predict the convergence of avalanches with a high degree of probability, since snow is an element of nature, which, by and large, is practically unpredictable. Of course, there are maps of dangerous areas and both passive and active methods are being taken to prevent this phenomenon. However, the causes and consequences of avalanches can be different and very noticeable. Passive methods include special shield barriers, forest areas, observation points for dangerous areas. Active actions consist in shelling areas of possible collapses from artillery and mortar installations in order to provoke the convergence of snow masses in small batches.

Snow avalanches sliding down from the mountains in any of the options are No matter how small or large they are. It is extremely important to take into account all the factors influencing the emergence of snow masses and their movement along an indefinite route to unknown targets, so as not to sacrifice too expensive gifts to the elements.

All about avalanches: interesting facts

1. The speed of an avalanche can reach 100-300 km/h. A powerful air wave instantly turns houses into ruins, crushes rocks, demolishes cable cars, uproots trees and destroys all life around.
2. Avalanches can come from any mountains. The main thing is that they are covered with snow cover. If there have been no avalanches in a certain area for 100 years, then there is always the possibility that they can occur at any time.
3. Approximately from 40 thousand to 80 thousand people lost their lives during the First World War, they remained buried under avalanches in the Alps. The data is approximate.
4. In America (California), people surrounded Mount St. Gabriel with deep ditches. Their sizes are equal to football fields. Avalanches descending from the mountain linger in these ditches and do not roll into settlements.
5. This destructive natural phenomenon is called differently by different peoples. The Austrians use the word "schneelaanen", which means "snow stream", the Italians say "valanga", the French - "avalanche". We call this phenomenon an avalanche.

Avalanche - a sudden movement of a mass of snow, ice, rocks down the slopes of mountains, posing a threat to human life and health. The condition for the formation of avalanches is a mountain snowy slope with a steepness of 15 - 30 degrees, heavy snowfall with an increase rate of 3 - 5 m/h. The most avalanche-prone periods of the year are winter-spring - at this time up to 95% of avalanches are recorded. The movement of an avalanche begins when the component of the gravity of the snow cover in the direction of the slope exceeds the force of adhesion of snow crystals to each other

Reasons for the movement of avalanches:

heavy snowfall or accumulation of a large amount of snow on the slopes when it is carried by the wind;

· low adhesion force between the underlying surface and recently fallen snow;

thaw and rain followed by the formation of a slippery layer of water between the underlying surface and freshly fallen snow;

a sharp change in air temperature;

mechanical, acoustic, wind impact on the snow cover.

The speed of avalanches is 20 - 100 m/s.

The striking factor of avalanches is a huge destructive force. Avalanches sweep away everything in their path, in the mountains they damage and destroy buildings, communications, power lines, roads, equipment, injure and kill people. main reason death in avalanches is suffocation (asphyxia). During the movement of an avalanche, it is almost impossible to breathe in it, snow clogs the respiratory tract, snow dust penetrates the lungs. In addition, a person can freeze, get mechanical injuries to the head and internal organs, fractures of the limbs or spine. This occurs as a result of impacts on the ground, rocks, trees, stones.

Avalanche protection includes:

study, observation, forecasting, informing the population about the possible threat of avalanches;

teaching people how to act safely in avalanche zones;

artificial induction of snow avalanches;

use of avalanche plantings;

creation of engineering structures in avalanche-prone places, including canopies, tunnels, corridors.

With the threat of snow avalanches, ski slopes, mountain roads and railways are closed, people are prohibited from going to the mountains, and the work of rescue teams is activated.

Landslide - sliding displacement of rock masses down the slope under the influence of gravity.

Up to 90% of landslides occur in areas located at altitudes from 1000 to 1700 m. This disaster most often occurs in spring and summer on slopes with a steepness of at least 19 degrees. Landslides also occur on the banks of large rivers.

According to the speed of movement, landslides are divided into:

on exceptionally fast (0.3 m/min);

fast (1.5 m/day);

on moderate (1.5 m / month);

on very slow (1.5 m / g);

on extremely slow (0.06 m/g).

Landslide - displacement of masses of rocks along the slope under the influence of its own gravity.

Landslide classification:

Reasons for the formation of landslides:

Increasing the steepness of the slope as a result of washing out the base with water;

weakening of the strength of rocks during their weathering or waterlogging;

seismic shocks;

· Violation of mining technology;

· deforestation and destruction of other vegetation on the slopes;

Improper agricultural practices for using slopes for farmland.

The thickness of a landslide is characterized by the volume of shifting rocks, which can be up to several million cubic meters.

collapse - it's a break and a fall large masses rocks from steep and steep slopes of mountains to river valleys, sea coasts due to the loss of adhesion of the detached mass with the parent base. Landslides can injure people, destroy highways, block equipment, create natural dams with the subsequent formation of lakes, and cause huge amounts of water to overflow from reservoirs.

Falls are:

· large - weight 10 million m3 And more;

medium - weight from several hundred to 10 million m3;

· small - several tens of cubic meters.

The formation of landslides is facilitated by the geological structure of the area, the presence of cracks on the slopes, crushing of rocks, and a large amount of moisture.

The collapse begins not suddenly. First, cracks appear on the slopes of the mountains. It is important to notice the first signs in time and take measures to save. In 80% of cases, collapses are associated with human activities. They occur during improper construction work, mining.

Mountains are undoubtedly one of the most beautiful and fascinating panoramas of the Earth. Many strive to conquer the majestic peaks, not fully realizing how harsh such beauty is. That is why, deciding on such a brave step, extreme people face difficulties in all their manifestations.

The mountains are a rather dangerous and complex terrain, in the expanses of which there is a constant mechanism of gravity, so the destroyed rocks move and form plains. Thus, the mountains eventually turn into small hills.

In the mountains, danger can always await, so you need to undergo special training and be able to act.

Definition of Avalanches

Snow avalanches are one of the most devastating, dangerous destructive phenomena of nature.

An avalanche is a rapid, sudden, minute process of moving snow with ice, occurring under the influence of gravity, water circulation and many other atmospheric and natural factors. Such a phenomenon most often occurs in the winter/spring period, much less often in summer/autumn, mainly at high altitudes.

It is always worth remembering that the avalanche is primarily a harbinger of weather conditions. Hiking in the mountains in bad weather: snowfall, rain, strong wind - is quite dangerous.

Most often, an avalanche occurs, lasting about a minute, while passing a distance of about 200–300 meters. It is extremely rare to hide or run away from an avalanche, and only if it became known about it at least 200–300 meters away.

The avalanche mechanism consists of a sloping slope, an avalanche body and gravity.

Sloping slope

Slope level, surface roughness in a big way affect avalanche risk.

A slope of 45–60° is usually not dangerous, as it gradually unloads during snowfalls. Despite this, such places, under certain weather conditions can create avalanches.

Snow will almost always fall from a slope of 60–65°, and this snow can linger on convex sections, creating dangerous blowouts.

Slope 90 ° - the collapse is a real snow avalanche.

avalanche body

Formed from accumulations of snow during an avalanche, it can crumble, roll, fly, flow. The type of movement directly depends on the roughness of the lower surface, the type of snow accumulation, and swiftness.

Types of avalanches according to the movement of snow accumulations are divided:

• to streaming;
• cloudy;
• complex.

Gravity

It acts on the body on the surface of the Earth, is directed vertically downwards, being the main mobile force that contributes to the movement of snow accumulations along the slope to the foot.

Factors affecting the occurrence of an avalanche:

• type of matter composition - snow, ice, snow + ice;
• connectivity - loose, monolithic, reservoir;
• density - dense, medium density, low density;
• temperature - low, medium, high;
• thickness - thin layer, medium, thick.

General classification of avalanches

Avalanches of powdered, dry recent snow

The convergence of such an avalanche usually occurs during heavy snowfall or immediately after it.

Powder snow is called fresh, light, fluffy snow, consisting of tiny snow flakes and crystals. The strength of snow is determined by the rate of increase in its height, the strength of the connection with the ground or previously fallen snow. It has a fairly high fluidity, which makes it possible to easily flow around a variety of obstacles. In different cases, they can reach speeds of 100–300 km / h.

Avalanches created by snowstorms

Such a convergence is the result of the transfer of snow by a blizzard. Thus, the snow is transferred to the mountain slopes and negative forms relief.

Avalanches of dense dry powder snow

They arise from snow a week old or more, which during this time is pressed, becomes much denser than freshly fallen. Such an avalanche moves more slowly, partially turning into a cloud.

landslide avalanches

They grow after the collapse of snow cornice blocks, which set in motion a large amount of snow.

Dust avalanches

An avalanche is characterized by a huge cloud or a thick layer of snow on trees and rocks. Created when dry, powdery recent snow melts. A dust avalanche sometimes reaches a speed of 400 km/h. Risk factors are: snow dust, strong shock wave.

Formation avalanches

They arise through the descent of layered snow, reach a speed of 200 km / h. Of all the snow avalanches are the most dangerous.

Avalanches from hard sheet snow

A stream is formed by the descent of solid layers of snow over a weak, loose layer of snow. They consist mainly of flat snow blocks resulting from the destruction of dense formations.

Soft plastic avalanches

Snow flow is formed by the descent of a soft layer of snow on the underlying surface. This type of avalanche is created from wet, settled, dense or moderately cohesive snow.

Avalanches of monolithic ice and ice-snow formations

At the end of winter, snow deposits remain, which, under the influence external factors become much heavier, turning into firn, eventually turning into ice.

Firn is snow cemented by frozen water. It is formed during temperature drops or fluctuations.

Complex avalanches

Consist of several parts:

• flying cloud of dry snow;
• a dense stream of formation, loose snow.

They arise after a thaw or a sharp cold snap, which is the result of the accumulation of snow, its separation, thereby forming a complex avalanche. This type of avalanche has catastrophic consequences and can destroy a mountain settlement.

Avalanches are wet

Formed from snow accumulations with the presence of bound water. Occur during the period of accumulation of moisture by snow masses, which occurs during precipitation and thaw.

Avalanches are wet

They arise due to the presence of unbound water in snow accumulations. Appear during a thaw with rain and warm wind. They can also occur by sliding a wet layer of snow over the surface of old snow.

Mudflow-like avalanches

They arise from snow formations with a large amount of moisture, the driving mass of which floats in a large volume of unbound water. They are the result of long thaws or rains, as a result of which the snow cover has a large excess of water.

The presented types of avalanches are quite dangerous, fast-moving flows, so you should not think that some are safer than others. The basic safety rules must always be followed.

Avalanche safety

The term avalanche safety refers to a set of actions aimed at protecting and eliminating the tragic consequences of avalanches.

As practice shows, in most accidents the extreme people themselves are to blame, who, without calculating their own strength, themselves violate the integrity and stability of the slopes. Unfortunately, there are deaths every year.

The main rule for the safe crossing of mountain ranges is the full knowledge of the passable territory, with all the dangers and obstacles, so that in an emergency you can safely, carefully leave the dangerous section of the path.

People going to the mountains, the basic rules of avalanche safety, be able to use avalanche equipment, otherwise the likelihood of falling under a snow blockage and death is very high. The main equipment is avalanche shovels, beepers, avalanche probes, float backpack, maps, medical equipment.

Before going to the mountains, it will be useful to take courses on rescue operations during a collapse, first aid, making the right decisions to save lives. Also milestone is a training of the psyche and ways to overcome stress. This can be learned in courses on working out techniques for saving people or yourself.

If a person is a beginner, it will be useful to read books about avalanche safety, which describe different situations, moments, stages of overcoming them. For a better understanding of avalanches the best option will personal experience obtained in the mountains in the presence of an experienced teacher.

Avalanche safety basics:

• mental attitude and preparation;
• obligatory visit to the doctor;
• listening to an avalanche safety briefing;
• taking with you a sufficient amount of food, small in volume, a spare pair of clothes, shoes;
• careful study of the route, upcoming weather conditions;
• taking a first aid kit, flashlight, compass, equipment on a hike;
• departure to the mountains with an experienced leader;
• studying information about avalanches in order to have an idea of ​​the degrees of avalanche safety during a collapse.

The list of avalanche equipment, which you need to be able to work with confidently, quickly, for your own safety and rescue of the victims:

• victim search tools: transmitter, avalanche ball, beeper, radar, avalanche shovel, avalanche probe, other necessary equipment;
• tools for checking snow flooring: saw, thermometer, snow density gauge and others;
• tools for rescuing victims: backpacks with inflatable pillows, avalanche breathing apparatus;
• tools for transporting victims, as well as medical equipment: bags, stretchers, backpacks.

Avalanche slopes: precautions

In order to avoid getting into an avalanche or if there is a high probability of an avalanche situation, you need to know a few important rules for avalanche safety and how to prevent it.

• move on safe slopes;
• do not go to the mountains without a compass, know the basics of the direction of the winds;
• move along elevated places, ridges that are more stable;
• avoid slopes with snow cornices hanging over them;
• return along the same road that went ahead;
• monitor the top layer of the slope;
• do tests on the strength of the snow cover;
• it is good and reliable to fix the insurance on the slope, otherwise the avalanche can drag a person with it;
• take on the road spare batteries for the phone and a flashlight, and also have in the memory of the mobile phone the numbers of all nearby rescue services.

If a group or a certain number of people still find themselves under an avalanche, you need to call rescuers, immediately starting the search on your own. In such a situation, the most necessary tools there will be an avalanche probe, a beeper, a shovel.

Every person who goes to the mountains should have an avalanche probe. This tool performs the function of sounding snow when prospecting work. It is a dismantled rod, two to three meters long. On security courses obligatory item is the assembly of an avalanche probe in order to assemble it in the shortest possible time when creating an extreme situation.

An avalanche shovel is indispensable when searching for victims, it is necessary for digging snow. It is more effective when combined with an avalanche probe.

A beeper is a radio transmitter that can be used to track a person covered in snow.

Only with coordinated, quick actions can a comrade be saved. After a thorough briefing on avalanche safety, a person will be mentally and physically ready to help others.

As a result, I would like to emphasize that hiking in the mountains cannot be carried out with bad weather, in the evening or at night, when crossing a dangerous area, it is imperative to use a rope belay, be sure to have beepers, flashlights, avalanche shovels and avalanche probes in your arsenal. Some part of these instruments must necessarily have a length of 3-4 m.

Observing all the rules, following the instructions, a person will protect himself from disastrous consequences and return home safely.

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The materials of the site www.snowway.ru and from other open sources were used.