What are avalanches: definition, causes, consequences

Often in the news there are reports of landslides that have occurred in various regions of the country or the world. As often we hear about avalanches that descended in mountainous areas. What are avalanches and avalanches? What damage can they inflict and is there a way to protect themselves from these phenomena of nature?

The collapses

The sudden separation of rocks from the main mass is called a collapse. He can arise in the mountains, on the steep banks of the seas, along the banks of rivers and valleys. Why is the land lying on the slope suddenly collapsing?

Most often, collapses occur for the following reasons:

- thanks to the water wash, the slope of the slope increased,
- if excessive waterlogging or weathering, the rock strength decreases,
- under the influence of earthquakes,
- thanks to human activities.

Not only soft soils of the soil are falling down. Frequent cases when a single shifted stone in the mountains, falling down the slope, carries with it hundreds of others, this is called a mountain collapse. Large collapses mainly arise as a result of tremors. Having happened near settlements, such incidents can turn into a real disaster. The most significant of them can even change the topography of the terrain. What are the landslides, you can clearly see by visiting Lake Sarez. It was formed due to the strongest collapse of 1911, which involved 2.2 billion cubic meters of rocks. A huge mass fell into the river, blocking it. This is how the lake was formed.

Kinds

Now it is clear what are the collapses. But it turns out that they are of different types. If less than 5 cubes of rocks participate in the collapse, this is usually considered a very small collapse. Small - up to 50 cubes. Average - from 50 cubes to a ton. Large includes more tons of rocks.

According to statistics, most of the collapses are small. They occur about 70% of the total number. Average - in second place: about 15%. Well, big ones happen quite rarely - less than 5% of the total. Very rarely - with a frequency of 0.05% - there are giant or even catastrophic collapses. In such incidents, a huge number of rocks are involved - millions and billions of cubes.

Effects

Most of the countries of the world know what the landslides are. And everyone knows that the scale is sometimes quite impressive. In addition, the consequences of collapses are catastrophic. Such incidents can cause the collapse of railway embankments, large debris, the destruction of homes and forests. It is not uncommon for large-scale landslides to be the cause of severe flooding and loss of life. Failures of this kind are most often due to strong earthquakes - from 7 points.

Stop

There are ways to deal with the landslides, but they can not protect anywhere, and not with any collapse it will work. For example, along the Black Sea coast is a railway from Tuapse to Sukhumi. On the one hand, the canvas is threatened by strong sea waves, from which it was decided to save the road with reinforced concrete structures. On the other hand - steep cliffs. From the falls, the road is protected by stone walls, stopping the falling stones. Similarly, protect and mountain roads. Unfortunately, these methods minimize the consequences of landslides only in cases of minor caving.

Where there is a significant overhang of rocks, there is only one way to save people and buildings from the disaster - independently, without waiting for a catastrophe, to destroy the rocks. The slopes are strengthened much less often, then they are wrapped around with hoops made of steel, the cracks appear appearing in the cement, etc. If there is a danger of collapse near settlements, the inhabitants have to be evacuated and the village transferred to another place.

Avalanches

Not only the rocks can crumble. In the mountains covered with snow, snow falls often occur - masses of snow falling from mountain slopes, often have a strong destructive effect. Why do avalanches happen? The fact is that the snow lies on the slopes of a heterogeneous layer. Its different layers have different stiffness of the coupling. And when the coupling between the layers is weak, the top layer simply slips.

Avalanches distinguish between superficial ones when one or several upper layers come down, and are deep-deep, taking away all the covering of the mountain slope, exposing the earth. Also, the avalanche can be wet or dry, depending on the water content. A snowball can start from one point, but it can also fall off a whole layer, leaving a line of separation behind it. An avalanche is considered to be almost any gathering of snow, capable of knocking a person off his feet.

In order to assess the probability of avalanche, many factors are taken into account. The most important is the weather. However, the evolution of the snow cover is no less important, but it directly depends on the weather. And since a skier or climber is capable of analyzing both of these indicators, he should not forget about either of them.

Consequences of avalanches

Currently, avalanches are a danger for the most part for athletes and tourists traveling to the mountains. Most often they fall in love with snowmobiling in the mountains, climbers and skiers. Strong avalanches are able to cover populated areas, sweeping away on their way all the living and nonliving. Sometimes mountain roads are in the way of the elements. Then the movement on them stops until the entire width of the avalanche is removed from the path.

Prevention

In the traditional winter recreation areas, it has long been common practice to artificially cause a collapse. Avalanche in this case will be small, its descent will not do any harm.

So, it is customary to make a forced collapse of the snow with the use of artillery pieces, mortars and other methods. In addition, in the path of a possible avalanche movement, structures are installed that can stop the snow or slow it down. To achieve the best results, it is necessary to use the whole range of measures known at the present time. Only by applying active, passive and engineering methods can people be saved from falling into a snow fall.

The avalanche is dangerous not only directly at the moment of descent. During the movement, the snow can be heated to plus temperature. And at the time of stopping, it forms a very hard crust, which is not easy to break even an ordinary person - with intact organs and in a calm mental state. A person who has fallen into an avalanche that has suffered various injuries, frightened, is almost impossible to do.