Hearing the big man say that, we think it makes sense. The place where you ski is sure to be safe and that there will be no avalanche-like disasters. Besides, the average ski resort will not be chosen at too high altitude. Generally speaking, large avalanches occur only when snow is covered at high altitudes and steep slopes.

The big man explained the usual ski resorts and the selection of those ski enthusiasts before and after, inside and out, for fear that the old ghost would not understand the truth. That kind of professional process is like a senior expert.

When the old ghost heard the big man say this, he knew that he had misunderstood what he meant, and hurriedly said, "Of course what I said is not what you said, but the latter!" Are those who are willing to die in search of skiing thrills, will they cause a big avalanche? ”

"Well, that's a good question!" The big man nodded and said, "This kind of thing you said really happens from time to time!" Moreover, there are not a few. According to scientific statistics, such examples abound. Except for some specific natural factors, they are generally the cause. These judgments were originally unfounded, but later, when their bodies and props were discovered, they were basically confirmed. ”

When the old ghost heard the big man say this, he nodded thoughtfully, as if he understood something.

The big man continued to give us popular science: "There are two forces that can lead to avalanches on snowy mountains: one is gravity! ”

"Gravity?" The old ghost asked.

The big man nodded and said, "Well, gravity pulls the snow down, but the cohesion of the snow wants to keep the snow in place." When this contest reaches its climax, even the slightest external force, such as the running of animals, the rolling stones, the wind, the slight shaking. Even shouting in the valley that the pressure exceeds the cohesive force that condenses the snow particles into clumps is enough to trigger a catastrophic avalanche. ”

"Damn, you're really sorry for saying that!" The more the old ghost listened, the more surprised he became, "Usually we climb to the top of the mountain because we are excited and we see the beautiful scenery. You can't help but shout! Do you feel this way? ”

When the old ghost finished speaking, he looked at me.

I heard the old ghost say this, and I think it's true! In the past, every time we climbed a mountain, we would yell, it was a kind of excitement, a sense of accomplishment that I had never felt before! Whoever you change, you can't help it.

When Duoduo and Lisa heard me say this, they both nodded in agreement, expressing their heartfelt approval.

"In that case. There is a high risk of triggering an unprecedented catastrophe! "That's how a lot of professional and unprofessional mountaineers die." Unfortunately, they don't know how they died until they die. ”

When the big man said something, we all nodded again and again. In fact, it is more not about approval, but about horror.

Lisa said, "I'm glad you said it early! Otherwise, I'd have screamed when I got to the top of the mountain! Just halfway up the mountain, I saw a beautiful scenery that I had never seen before, and I wanted to scream. But. Think about it, let's wait until you reach the top of the mountain to call again! So, I held back. ”

"Hey, hey. Sister, can you not be so dirty? The old ghost saw that there was an opportunity to hit Lisa, so he said "in the stitches": "You have a good voice, maybe you will kill us." ”

"Haven't I been called out yet? You're afraid of death! Your life is precious! Lisa said angrily.

The old ghost was just about to say something to fight back, but I saw that the big man didn't seem to finish speaking, so I quickly interrupted the old ghost and said, "Okay." Well, nothing to argue. Big brother hasn't finished talking yet, so let's let the family finish talking! If you can save the time, because of a small move, it will cause an uncontrollable disaster. ”

When the old ghost and Lisa heard me say this, they stopped arguing. Let's look at the big one.

"Just like the usual wind, it's the most common natural cause of avalanches," said the big man. Not only does the wind cause a large accumulation of snow, but it also causes snow particles to condense, resulting in a hard and brittle layer of snow. As a result, the upper layer of snow can slide along the lower layer of snow, causing large-scale avalanches.

In addition to hillside morphology, avalanches are also dependent on human activity over a large extent. Experts estimate that 90% of avalanches are caused by victims or their teammates. This man-made avalanche is known as a 'man-made recreational avalanche'. Skiing, hiking, or other winter sports enthusiasts often inadvertently become the trigger for avalanches. ”

What the big man said was convincing us all, and what he said was that we nodded our heads again and again. This so-called "man-made leisure avalanche" also echoes the situation that the big man said before.

The big man continued: "There are two types of avalanches: wet avalanches and dry avalanches, and they have different geomorphological and climatic conditions for formation and occurrence.

'Wet avalanches', also known as 'block avalanches', are one of the most dangerous types of avalanches. It usually occurs a few days after a rainfall and is formed as the surface snow melts and seeps into the underlying snow and freezes again, forming a 'wet snow layer'.

In late winter or early spring, the temperature continues to rise after snowfall. This makes it impossible for the new wet snow layer to be lightly attached to the original snow and ice, which is less dense. It then slides downward, causing an avalanche. Wet avalanches are generally lumpy, slow, heavy, dense, and grow larger on the slopes like ink stains. As a result, wet avalanches are also more destructive.

This type of avalanche is formed in an area usually on a slope with a slight slope. Because the powder snow (loose snow) on the steep slope is almost finished, it is the turn of the relatively gentle slope to have an avalanche. It glides more slowly than an airborne avalanche, bringing up trees and rocks along the way, producing larger snow gravel.

But once you get caught up in a lumpy avalanche, you're never as lucky as you are in a dry avalanche. The chances of surviving are almost zero. And once it stops, it freezes immediately, often making rescue efforts very difficult. It is also tantamount to creating a secondary obstacle to the rescue work, thus greatly reducing the survival rate. ”

The big man's words, we are all amazed and frightened. Before we could come to our senses, we heard the big man say again: "A dry avalanche, also known as a powder avalanche, carries a lot of air, so it will be like a fluid snow mist." The avalanche velocity is extremely high, and they soar down from the high mountains, engulfing a qiē in the blink of an eye. They even rush down the hill before going up the opposite hill.

Generally speaking, the snow on the mountains has not had time to melt shortly after the heavy snow has stopped. Or before the melted water seeps into the underlying snow and freezes, the snow is 'dry' and 'powdery'. When an avalanche occurs in this type of snow, the air waves will be very large, and the bottom layer will easily form an air cushion.

When an expedition encounters such an avalanche, a person can be entrapped in an avalanche body and fly down with the avalanche. However, dry avalanches or powder avalanches pose a relatively small fatal threat to explorers. Generally speaking, there is a high probability that people who have been hit by such avalanches will survive. Unless one of the ......"

"What's the situation?" The old ghost asked impatiently.

"It's just buried too deep in the ice and snow, and teammates or companions can't even find it!" The big man said, "If he encounters something like that, he can only be considered unlucky." However, if you encounter such a situation, remember to make your 'volume' larger. In this way, it will not be buried too deep in the ice and snow. ”

The words of the big man are like "Daigo empowerment". It also makes us feel as if we have experienced an avalanche in such a short period of time.

In fact, before the big man explained the cause of the avalanche, I also knew that it was dangerous and severe: large avalanches would bury the houses of the people living under the mountain, and even bury the local residents alive. Not to mention the lonely humans who are already insignificant compared to the avalanche.

Most of the avalanche formation areas are in the upper part of the high mountains, where there is a lot of snow and thick snow. For example, high snow eaves, slopes with slopes of more than 50-60 degrees, and the lower end of hanging glaciers are all areas of avalanche formation.

Underneath the avalanche formation zone is often a U-shaped trench that runs straight from top to bottom. Due to the frequent avalanches leading to guò, the inside of the trough is still very smooth despite being covered in snow. If there are no large undulations or obstacles, it can be up to a few hundred meters long and twenty or thirty meters wide or slightly larger. But not too wide, otherwise the snow and ice will not be very concentrated and will not form a large avalanche.

Avalanches usually only stop when they encounter special terrain, such as at the foot of a mountain where the slope suddenly slows down. Or hit a cliff and let all the snow fly. From the perspective of geomorphology, most of them will be cones, so they are also called "avalanche cones" (or "avalanche piles").

Most avalanches occur in the winter, or in the spring, when the snow is very heavy. Especially around the time of the blizzard, which is the peak of avalanche occurrence.

Although the current season is not late winter and early spring, the weather situation in front of us is really not optimistic! Depending on the weather, a snowstorm will happen sooner or later!

Generally, just after a snowstorm, the snow is very soft and the adhesion is relatively small. Once a small piece is destroyed, the rest of the piece will be like a plate of loose sand or "dominoes", creating a chain reaction and falling rapidly.

In spring, due to the long thaw period, when the temperature rises, the snow surface melts, and the snow water penetrates deep into the snow layer drop by drop. This loosens the otherwise solid snow, greatly reducing the cohesion and breaking strength between the snow covers, making it easy for the snow layers to slip between them.

As far as China's alpine mountains are concerned, the alpine terrain of the Himalayas, the Nianqing Tanggula Mountains and the Hengduan Mountains on the southwestern border is prone to avalanches because they are mainly controlled by the Indian Ocean monsoon, with abundant precipitation throughout the year, and the upper part of the alpine mountains receives more snow and snow in winter and spring. (To be continued......)