Often in the news there are reports of collapses that occurred in various regions of the country or the world. Just as often we hear about avalanches that descended in mountainous areas. What are landslides and avalanches? What damage can they do and is there a way to protect themselves from these natural phenomena?
Crashes
The sudden separation of rocks from the main mass is called a collapse. It can occur in the mountains, on the steep shores of the seas, along the banks of rivers and in valleys. Why does the ground lying on the slope suddenly collapse?
Most often, collapses occur for the following reasons:
- due to water washing, the steepness of the slope increased, - with excessive waterlogging or weathering, the strength of rocks decreases, - under the influence of earthquakes, - due to human activity.
It's not just soft soils that collapse. There are frequent cases when a single moving stone in the mountains, falling down the slope, drags hundreds of others with it, this is called a mountain collapse. Large landslides mainly occur as a result of tremors. Happening nearsettlements, such incidents can develop into a real disaster. The most significant of them can even change the topography of the area. What are landslides, you can clearly see by visiting Sarez Lake. It was it that was formed due to the strongest collapse of 1911, in which 2.2 billion cubic meters of rocks were involved. A huge mass fell into the river, blocking it. This is how the lake was formed.
Views
Now it's clear what collapses are. But it turns out they are different. If less than 5 cubes of rocks are involved in the collapse, this is considered to be a very small collapse. Small - up to 50 cubic meters. Medium - from 50 cubic meters to a ton. The large one includes over a ton of rocks.
According to statistics, most of the collapses are small. They occur in about 70% of the total. Medium - in second place: about 15%. Well, large ones occur quite rarely - less than 5% of the total. Extremely rarely - with a frequency of 0.05% - giant or even catastrophic collapses occur. A huge number of breeds are involved in such incidents - millions and billions of cubes.
Consequences
Most of the countries in the world know what collapses are. And everyone knows that the scale is sometimes quite impressive. In addition, the consequences of collapses can be catastrophic. Such incidents can cause collapse of railway embankments, large blockages, destruction of dwellings and forests. There are frequent cases when giant collapses werecausing severe flooding and loss of life. Collapses of this kind most often occur as a result of strong earthquakes - from 7 points.
Stop
There are ways to deal with collapses, but they are not able to protect everywhere, and it will not work with any collapse. For example, along the Black Sea coast there 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 protect the road with reinforced concrete structures. On the other hand, steep slopes. The road is protected from landslides by stone walls that stop falling stones. Mountain roads are protected in the same way. Unfortunately, these methods only minimize the effects of collapses in cases of minor collapses.
Where the rocks overhang significantly, there is only one way to save people and buildings from disaster - to destroy the rocks on your own, without waiting for the catastrophe. Strengthening the slopes is done much less often, then they are surrounded by steel hoops, the cracks that appear are filled with cement, etc. If there is a danger of collapses near settlements, residents have to be evacuated, and the village must be moved to another place.
Avalanches
It's not just rocks that can collapse. In the mountains covered with snow, snowfalls often occur - masses of snow that fall from the mountain slopes often have a strong destructive effect. Why do avalanches happen? The fact is that the snow lies on the slopes in a heterogeneous layer. Its different layers have different coupling stiffness. And when the adhesion between the layers is weak, the top layerjust slides off.
Avalanches distinguish between surface, when one or more upper layers come off, and full-deep, taking away the entire covering of the mountain slope, exposing the earth. Also, an avalanche can be wet or dry, depending on the water content. A snowfall can start from one point, but it can also break off in a whole layer, leaving behind a separation line. Almost any snowfall is considered an avalanche, capable of knocking a person down with its movement.
In order to assess the likelihood of an avalanche, many factors are taken into account. The most important is the weather. However, the evolution of snow cover is no less important, but it directly depends on the weather. And since the skier or climber is able to analyze both of these indicators, he should not forget about any of them.
The consequences of avalanches
Currently, avalanches pose a danger mostly to athletes and tourists going to the mountains. Most often, snowmobilers in the mountains, climbers and skiers fall into them. Strong avalanches are capable of covering settlements, sweeping away everything living and inanimate in their path. Sometimes mountain roads get 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 traditional winter recreation areas, it has long been a common practice to artificially cause a collapse. The avalanche in this case will be small, its descent will not cause harm.
Thus, it is customary to make a forced collapse of snow using artillery, mortars and other methods. In addition, structures are installed in the path of the possible movement of an avalanche that can stop the progress of snow or slow down its movement. To achieve the best results, it is necessary to use the full range of measures currently known. Only by applying active, passive and engineering methods can people be saved from falling into a snow avalanche.
An avalanche is dangerous not only right at the moment of descending. During the movement, the snow is able to heat up to positive temperatures. And at the moment of stopping, it forms a very hard crust, which is not easy to break even for an ordinary person - with intact organs and in a calm mental state. It is practically impossible for a person who has fallen into an avalanche, received various injuries, and is frightened to do this.
