Snow Avalanches - Alternative View

Snow Avalanches - Alternative View
Snow Avalanches - Alternative View

Video: Snow Avalanches - Alternative View

Video: Snow Avalanches - Alternative View
Video: Avalanches 101 | National Geographic 2024, March
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The famous French avalanche researcher Pierre Monsan describes the impressions of a man caught in an avalanche in Chamonix in the Alps. “My partner and I worked to fix the mid-slope lift support. At night there was heavy snowfall and a sharp wind. The snow cover has increased greatly, but no one foolishly attached any importance to this. Suddenly there was a sharp crack. I raised my head and saw how a transverse crack formed in the upper part of the slope on a white field and a huge snow slab broke off and rushed down. We barely had time to jump off the support. There was a low roar, and the shockwave knocked them off their feet. Out of the corner of my eye, I noticed the falling support of the lift. In the next instant, it seemed that there was a continuous snowstorm around, fine prickly snow crammed into the eyes, ears, mouth and nose.

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It was impossible to breathe, something heavy, like a bear, fell on me and dragged me down. After a few seconds, the movement stopped, I could hardly blink: there was absolute darkness around, it was not possible to determine where the top was, where the bottom was. I tried to free myself from the weight that had piled on me, but only buried myself deeper into the snow. Gradually the snow became more and more dense, hardening and turning into ice. A deadly terror seized me, the ice shell was unbreakable. Suddenly the movement resumed, I was turned over my head, the sense of space was lost. A minute later the snow stream stopped, breathing became easier, I realized that I was carried to the surface."

When Pierre got into an avalanche, the radio beacon automatically turned on, so that the rescuers arrived at the crash site within an hour. He could not walk, as he broke his leg and was also very cold. Unfortunately, the partner's beacon did not turn on. Rescuers searched for him for several days and still found him along an avalanche cord, a long red ribbon tied to his belt. The unfortunate man was already dead, although he had dug a small tunnel right in front of him, trying to get out, so that his hands were tattered with blood. Unfortunately, there was not enough air and he died of suffocation. Monsan's death and the terrible moments suffered in the avalanche made an indelible impression on Monsan. He graduated from the Sorbonne with a degree in Meteorology and took up the study of avalanches.

An avalanche is a rapidly moving landslide of snow from the side of a mountain or hill. Avalanches are capable of moving at a speed of 20-30 meters per second, the snow mass gains this speed in 5 seconds after the start of movement. The sleet avalanches travel a little more slowly, covering about 7 meters per second. The avalanche of loose snow begins at one point, it expands as it moves. These avalanches are the least dangerous and usually do not bury their victims deep in the snow, but they can push a person off a steep cliff or cliff. The most dangerous are avalanches - slabs. They consist of a solid frozen crust. Often the victim summons it by traversing the slope and cutting the snow.

A crack forms across the slope, and a huge slab of snow slides down like a glass dish from an incline. Ice avalanches form when a glacier reaches a steep slope. Glaciers flow down mountain slopes like rivers under the influence of gravity. When a sharp cliff comes across on their way, chunks of ice break off and fall down with great speed. Ice avalanches, unlike snow ones, are not associated with weather factors, air temperature, wind, etc.

The next type of avalanche is caused by the fall of snow eaves, which often form on the crests of mountains. Often they look very beautiful and look like frozen ocean waves, they are formed by the prevailing winds in the area. The snow of the cornices is very dense and therefore fragile. When the mass of the cornice exceeds the critical value, the latter falls down.

What makes the seemingly harmless snow fields suddenly break down and slide down the slope? Rapid temperature changes and winds are common causes. With a sharp warming, the upper layer of snow on the slope melts; with the subsequent cooling, the melted layer turns into ice. If there is then heavy snowfall, the new masses of snow will not be able to hold onto the ice and will slide down. Another reason for an unexpected avalanche is the so-called “deep frost”. The warmth of the ground on which snow has fallen can melt the bottom layer. The colder upper layers cause this layer to freeze. The result is a kind of ice slide.

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But the main cause of avalanches is wind. In the mountains, very strong storm winds often blow, capable of moving large masses of snow from place to place. The wind manages to sweep 10 times more snow than heavy snowfall in the same period of time. The weight of the new snow overloads the lower layers and an avalanche forms.

The popular myth that a loud sound can trigger an avalanche is groundless. “This is a filmmaker's invention,” said Bruce Tremper of the Utah Avalanche Forecasting Center. In twenty years of his work at the Center, there was no case when an avalanche was caused by the scream or noise of a helicopter engine running. Most often, avalanches are caused either by the victim himself or by someone from her company. As already mentioned, people sometimes trim the layer of snow by crossing the mountainside across. Tracks from skis and snowmobiles can also upset the delicate balance in the grip of a mass of snow, and then it rushes down with a roar.

Common victims of avalanches are climbers, skiers, rock climbers and snowmobilers. The latter account for 50 percent of all victims. Usually, a person caught in an avalanche does not have time to escape because of its tremendous speed. The avalanche drags rocks and trees with it, which can injure a person. Inside the snow mass, a person's mouth and nose are instantly clogged with snow dust, so it is impossible to breathe - 90 percent of avalanche deaths are caused by asphyxiation. Immediately after stopping the movement, the snow is compressed, forming a mass like concrete, and the person is walled up inside the snow prison. He just can't move. An ice mask forms on the face, which prevents breathing.

Usually, the victim has only 30 minutes left to try to escape from captivity, after this time, oxygen runs out inside the cavity in which the victim is located. In addition, severe hypothermia of the body poses a mortal danger. More often than not, even if the rescuers manage to dig out the victims, they are already dead. Since the 1950s, the number of avalanche victims has steadily increased, mainly due to the increasing popularity of mountain recreation. In the 90s, the death toll from the white death doubled due to the invention of snowboarding and the snowmobile.

It happens that kilotons of snow block roads and settlements remain cut off from the rest of the world. This happened recently in Alaska, when the town of Greenwood was isolated by an avalanche for several days. And a couple of years ago in Norway, an avalanche blew a bus right into the sea, killing five people in the process.

Snow monsters continue to collect tributes around the world.