Avalanche formation? How to deal with the arrival of avalanches

The formation and development of an avalanche can be divided into three parts: the formation zone, the pass zone, and the accumulation zone.

Most of the formation area is in the upper part of the mountain, where there are many thick and thick snow. For example, high snowball slopes, snow slopes with a slope of more than 50-60 degrees, and the topography of the lower part of the glaciers are avalanche formation areas. Experienced alpine explorers should be able to see. The avalanche pass-through zone is immediately below the formation zone and is often a U-shaped channel straight up and down. Due to the often avalanche pass, the slot is still very smooth despite the snow cover. There is basically no large undulations. Or obstacles, up to several hundred meters in length, 20-30 meters in width or slightly larger, but not too wide, otherwise the snow and ice that slide down will not be very concentrated and will not form a large avalanche. The accumulation area is also located immediately below the formation area, where the avalanche is stopped at the foot of the slope due to a sudden slowing down of the slope. The landform is mostly a cone, so it is also called an avalanche cone (or avalanche stack). .

Avalanches can be classified as dry avalanches, wet avalanches, or powder avalanches and block avalanches. Their formation and occurrence have different geomorphological and climatic conditions. In general, the snow has just stopped, the snow on the mountain has not yet melted before it melts, or before the melted water has infiltrated into the lower snow and then freezes, the snow is “dry” and “powder”. When this kind of snow avalanche occurs, air cushions are easily formed on the bottom layer of the air. When an expedition team encounters such an avalanche, people can be trapped in an avalanche and fly down with an avalanche.

The occurrence of avalanches also has spatial and temporal patterns. As far as the Chinese mountains are concerned, the high mountains on the southwestern border, such as the Himalayas, Nyainqentanglha Mountain, and the Hengduan Mountains, are dominated by the Indian monsoon, with the exception of the rainy season (May-October) and the dry season (January-April). Precipitation is abundant throughout the year, and winter and spring snowfall and snow accumulation are also abundant in the upper part of the mountain. Therefore, it is prone to avalanches. In addition, in the Tianshan Mountains and the Altai Mountains, due to the effects of the Arctic Ocean's polar air masses, there are also many precipitations in winter and spring, so the avalanche is also more frequent this season.

The physical principle of the avalanche is very simple. The snow on the hillside receives two forces: one is the gravitational force of the earth and the other is the cohesion of the snow. Between these two forces is a tug-of-war battle between you and the United States. Earth's gravity attempts to pull the snow down the slopes, and the cohesion of the snow makes the bodies stick to each other and stay on the hillside.

The cohesiveness of snow is related to the thickness of the snow, and when the continuous snowfall makes the snow on the hillside reach a certain thickness, it is prone to avalanches. When the temperature rises in the spring, the surface of the snow melts and melted water seeps into the snow layer. This reduces the cohesion, internal friction and breaking strength of the snow, especially when the meltwater seeps into the bottom of the snow. Like a lubricant, the snow layer slides easily. When the snow on the hillside becomes more unstable due to various reasons above, the avalanche can be triggered as soon as there is a change in the external factors. For example, a slight earthquake, an animal walk, a rolling stone strike, and even a loud scream can trigger an avalanche at this moment.

In mountainous regions where the wind is relatively abundant, the wind can also cause an avalanche of snow. In places where the mountains are leeward, snow can blow snow into the air. Like the roof of our house, we call it a sledge. Once the snowball's own weight exceeds the breaking strength of the snowball, the snowball collapses on its own, causing the snow on the slope below to fall.

In the seasonal snowpack area in the western part of the western Tianshan Mountains, several avalanches triggered by animals such as blue sheep and red deer can be seen every winter. These animals find food along snow-covered slopes and sometimes they unfortunately stepped on the snow and were buried in avalanches. .

In addition, deforestation can also reduce the stability of snowpack on slopes. Forests and shrubs play an objective role in preventing snow from falling. Therefore, the logging of trees in the avalanche area should be prohibited. In the Swiss Alps, where avalanches are frequent, local laws explicitly prohibit the cutting of trees in avalanches. All illegal residents will be driven out of the country.

Why is the power of avalanche so great?

The world champion of human sprinting, but running 11 meters per second; animal kingdom sprint champion Cheetah's lightning speed at hunting, but running 30.5 meters per second; a powerful typhoon at level 12, but every second Run 32.5 meters. However, the avalanche can achieve an amazing 97 meters per second. For example, in the large avalanche of Peru in 1970, the avalanche flew 14.5 kilometers in less than three minutes. In other words, the average speed is nearly 90 meters per second.

Deng Xueshan should pay attention to what

If you must move in the snowpack areas of mountains and mountains, you should pay special attention to avoid artificially triggering an avalanche. After the snowfall, climbing can not be done immediately. In general, moderately heavy snowfall must go after a day before going uphill. After the heavy snowfall, especially after several days of heavy snowfall, you must stay for three or four days before climbing on the snow. Because the new snow is relatively loose, the cohesion is poor, and people are active on it, which easily triggers an avalanche.

rescue

When climbing a snow-covered slope, do not cross the slope. Because it crosses slopes, it is easy to crack the snow layer and induce an avalanche. It's best to go straight to the top of the hill. Of course, if this is done, physical exertion will be greater. In the case of a last resort, the zigzag-shaped climbing route may be used, but the angle of the zigzag character should be enlarged as much as possible. When walking, the pace should be light. To be steady, do not open another footprint. Take a walk in front of the person's footprints. When snow is relatively unstable, do not scream or sing loudly. Because sometimes, sound waves can also impact snow and cause collapse. Due to the need of work, when crossing non-snow slopes, each person's interval should be farther and progress one by one. Everyone must maintain a high degree of vigilance. Once anyone finds that there is a danger of a collapse due to a snow slide, he will shout out "Avalanche!" to prepare people behind him. If the snow beneath my feet is already slipping, we must first insert the ice sheet on the snow and try to stop myself on the snow surface.