What are the classification and characteristics of snowstorms?

Snow disaster, also known as white disaster, is a natural phenomenon caused by long-term heavy snowfall and a frequent meteorological disaster. Due to the excessive snowfall in winter, the thick snow cover and the long duration of the snow cover, human activities have been affected to varying degrees. Snow disasters mainly occur in stable snow-covered areas and unstable snow-covered mountainous areas, and occasionally appear in instantaneous snow-covered areas.

Snow disaster classification

A terrible snowstorm

Snowstorms can be divided into two types according to their climatic laws: sudden and persistent. (1) During or after the snowstorm, there is a sudden snowstorm, and the thick snow that lasts for several days poses a threat to livestock. This type is more common in late autumn and spring with changeable climate. (2) The thickness and density of the snow that is harmful to livestock gradually increase with the snowfall, and it takes a long time for the snow to stabilize. This type can last from late autumn to the following spring.

According to the formation conditions, distribution range and manifestations of snow disasters, snow disasters can be divided into three types: avalanche, wind-blown snow disasters (snow flow) and snow disasters in pastoral areas.

According to the stability of snow, the snow in China can be divided into five types:

(1) Permanent snow: The amount of snow is greater than that of the current year, and the snow will not melt all the year round.

(2) Stable snow (continuous snow): seasonal snow with continuous spatial distribution and snow accumulation time (more than 60 days).

(3) Unstable snow (discontinuous snow): Although there is snow every year and the temperature is low, the snow is discontinuous in space and mostly distributed in points. The number of snow days in time is 10 ~ 60 days, which is intermittent.

(4) Instantaneous snow: It mainly occurs in South China and Southwest China where the average temperature is relatively high. In the year when the monsoon is particularly strong, due to the attack of cold wave or strong cold air, large-scale snowfall occurs, but it melts quickly, resulting in short-term (generally no more than 10 day) snow on the surface.

(5) No snow: Except for some high-altitude mountainous areas, it doesn't snow all the year round. Snow disasters mainly occur in stable snow-covered areas and unstable snow-covered mountainous areas, and occasionally appear in instantaneous snow-covered areas.

Snow can play an active defensive role in the wintering and heat preservation of pasture, and snowmelt in dry season can increase soil moisture and promote the regrowth of pasture. Snow is also the main water source of water-deficient or waterless grassland in winter and spring, which can solve the problem of drinking water for people and livestock. Too much snow, too deep snow and too long duration make it difficult for livestock to eat grass, or even unable to eat grass, leading to snowstorms.

Snow disaster index

Usually, the depth of grassland snow is used as the primary sign of snow disaster. Due to the different growth heights of grassland and pasture, the depth of snow forming snowstorm is also different. Blizzard index: (1) light blizzard: the snowfall in winter and spring is equivalent to more than 120% of the snowfall in the same period of the year; (2) Moderate blizzard: the snowfall in winter and spring is equivalent to more than 140% of the snowfall in the same period of the year; (3) Heavy snowstorm: The snowfall in winter and spring is equivalent to more than 160% of the snowfall in the same period of the year. Snow disaster index can also be expressed by other physical quantities, such as snow depth, density and temperature. However, the biggest advantage of the above indicators is that they are easy to use and the data are easy to obtain.

Blizzard law

Law of snow disaster in pastoral areas: According to the analysis of investigation data, snow disaster in grassland pastoral areas in China has the law of 10. As for the general snowstorm, its frequency is more frequent. According to statistics, pastoral areas in Tibet are about once every two to three years, and so are pastoral areas in Qinghai. In pastoral areas of Xinjiang, due to the great differences in climate and geography, the frequency of snowstorms varies greatly. The frequency of snow disasters in winter pasture and spring and autumn pasture in Altai Mountain, western Junggar, northern Xinjiang along Tianshan Mountain and western mountainous area of southern Xinjiang reaches 50% ~ 70%, that is, snow disasters occur in 5 ~ 7 years in 10. Other regions are below 30%. Snowstorm-prone areas are often serious, such as Altay, Fuyun and other places. The frequency of snowstorms is as high as 70%, and severe snowstorms are as high as 50%. On the contrary, areas with low frequency of snowstorms are often areas with light snowstorms. For example, the frequency of snowstorms in hot springs is only 5%, and it is a mild snowstorm. However, no matter which pastoral area, snowstorms occur in young years. During a snowstorm, winter snow usually begins at 10, and Chun Xue usually ends in April. What is more harmful is generally the so-called "sitting in winter snow" formed by heavy snow in late autumn and early winter. Then there was a continuous snowfall, which made the grassland snow thicker and thicker, so that the snow that harmed livestock lasted all winter. Snow disaster warning

Snow disaster warning signals are divided into three levels, which are represented by yellow, orange and red respectively. Yellow is the third-level defense state, with orange on it, and the last red indicates the first-level emergency and dangerous situation.

(1) Yellow warning signal of blizzard: 12 hours may have snowfall affecting traffic or animal husbandry. ① Relevant departments should prepare for snow prevention; (2) The transportation department should prepare for road snow melting; (3) Prepare grain and grass in agricultural and pastoral areas. (2) Snow disaster orange warning signal: within 6 hours, there may be snowfall that has a great impact on traffic or animal husbandry, or there has been snowfall that has a great impact on traffic or animal husbandry and may continue.

(1) Relevant departments shall do a good job in road cleaning and snow melting; ② Drivers should drive carefully to ensure safety; (3) Drive the wild livestock to the pen for feeding. (3) Blizzard in red warning signal: There may be snowfall that has a great impact on traffic or animal husbandry within 2 hours, or there has been snowfall that has a great impact on traffic or animal husbandry and may continue. ① Close road traffic when necessary; ② Relevant emergency departments should be ready to start the emergency plan at any time; ③ Do a good job in disaster relief in pastoral areas. Alert-early warning of snowstorm

Blizzard warning signals are divided into four levels, which are represented by blue, yellow, orange and red respectively.

(1) blue warning signal of blizzard: 12 hours, the snowfall will reach more than 4 mm, or it has reached more than 4 mm and the snowfall continues, which may have an impact on traffic or agriculture and animal husbandry.

(a) the government and relevant departments shall, in accordance with their duties, make preparations for snow disaster prevention and freezing injury prevention; (2) Traffic, railway, electric power, communication and other departments patrol and maintain roads, railways and lines, and do a good job in road cleaning and snow melting; ③ Pedestrians should pay attention to cold prevention and anti-skid, drivers should drive carefully, and vehicles should take anti-skid measures; (4) Farming and pastoral areas and aquaculture should reserve feed and prepare for snow disaster and freezing injury; ⑤ Reinforce temporary structures that are easily crushed by snow, such as scaffolding.

(2) Yellow warning signal of blizzard: 12 hours, the snowfall will reach more than 6 mm, or it has reached more than 6 mm and the snowfall continues, which may have an impact on traffic or agriculture and animal husbandry.

(a) the government and relevant departments shall, in accordance with their duties, implement measures to prevent snowstorms and freezing injuries; Transportation, railway, electric power, communications and other departments should strengthen the inspection and maintenance of roads, railways and lines, and do a good job in road cleaning and snow melting; ③ Pedestrians should pay attention to cold prevention and anti-skid, drivers should drive carefully, and vehicles should take anti-skid measures; (4) Farming and pastoral areas and aquaculture should prepare enough feed to prevent snowstorm and freezing injury; ⑤ Reinforce temporary structures that are easily crushed by snow, such as scaffolding.

(3) Snowstorm orange warning signal: The snowfall will reach more than10mm within 6 hours, or it has reached more than10mm and the snowfall continues, which may or has already caused a great impact on traffic or agriculture and animal husbandry.

(a) the government and relevant departments shall, in accordance with their duties, do a good job in emergency work to prevent snowstorms and freezing injuries; Transportation, railway, electric power, communications and other departments should strengthen the inspection and maintenance of roads, railways and lines, and do a good job in road cleaning and snow melting; ③ Reduce unnecessary outdoor activities; (4) Reinforce scaffolding and other temporary structures that are easily crushed by snow, and drive the outdoor livestock into the shed for feeding.

(4) Blizzard in red warning signal: The snowfall will be above15mm within 6 hours, or it has been above15mm and the snowfall continues, which may or has caused a great impact on traffic or agriculture and animal husbandry.

(1) The government and relevant departments shall, in accordance with their duties, do a good job in emergency rescue of snowstorms and freezing injuries; (2) suspend classes or business when necessary (except for special industries); (3) When necessary, the aircraft will be suspended from taking off and landing, the train will stop running, and expressway will be temporarily closed; ④ Do a good job in disaster relief in pastoral areas.

Snow disaster prevention

Five measures to prevent snow disaster in agricultural production;

(1) Effective anti-freezing measures should be taken as soon as possible to resist the invasion of strong and low temperature to overwintering crops, especially to prevent the harm of continuous low temperature to strong and weak seedlings. (2) Strengthen the management of greenhouse vegetables and underground overwintering vegetables to prevent the harm of continuous rain, snow and low temperature weather, and clear the snow in the greenhouse in time after snow, which not only reduces the pressure of plastic film, but also helps to increase temperature and light transmission; At the same time, strengthen the storage management of all kinds of winter vegetables and fruits.

(3) In rainy and snowy weather, the "three ditches" should be cleaned in time to reduce humidity and drain water, so as to prevent long-term water accumulation in the field caused by continuous rainy and snowy weather and affect the growth and development of wheat and vegetable roots. At the same time, it is necessary to strengthen field management, intertillage and loosen the soil, eradicate weeds and improve their cold resistance. Do a good job in pest control.

(4) Wheat and vegetables should be covered with soil in time to improve cold resistance. If organic fertilizer such as pig manure can be covered, the effect of protecting seedlings from wintering will be better.

(5) Do a good job of wind protection and reinforcement in the greenhouse, pay attention to the heat preservation and warming of the greenhouse, reduce the occurrence of vegetable diseases, and ensure the normal supply of vegetables.

Severe snowstorm in southern China in 2008

Snowstorm in China in 2008

On June 65438+ 10/0, 2008, a snowstorm broke out in the south. The severely affected areas are Hunan, Guizhou, Hubei, Jiangxi, northwestern Guangxi, northern Guangdong, western Zhejiang, southern Anhui and southern Henan. As of February, 2008, 12, 2 1 provinces (autonomous regions, municipalities and corps) in China were affected by freezing rain, snow and ice disasters to varying degrees, resulting in 107 deaths, 8 missing, and 15 12000 emergency. The affected area of crops was 65.438+0.77 billion mu, and the harvest was 2530 mu. The damaged forest area is nearly 260 million mu; 354,000 houses collapsed; Causing direct economic losses of RMB111100 million yuan.

What is the weather cause of this snowstorm? The main reason for the formation of large-scale rain and snow weather process is the abnormal atmospheric circulation, especially in Eurasia.

As we all know, the atmospheric circulation has its own operating rules, and it maintains a stable circulation state for a certain period of time. There is a low-value system in the southwest of Qinghai-Tibet Plateau, while Siberia maintains a relatively high-value system, namely, meteorological low-pressure system and high-pressure system. These two systems have existed in these two areas for a long time, and the low-pressure system has brought abundant precipitation to the southern part of China, mainly in the southern sea and the Indian Ocean. Cold high pressure from Siberia pushes cold air to the south. Obviously, under normal circumstances, the cold air from Siberia is the main factor that controls our country in winter, making most parts of our country dry and cold.

On June 5438+ 10, 2008, the warm and humid airflow in the southwest affected most parts of China, the high-pressure system in the north was stable, and cold air was continuously transported from Siberia to the south. Cold and warm air forms an intersection zone in the middle and lower reaches of the Yangtze River and the south. The density of cold air is relatively high, and warm air will slide upward along the cold air layer, so the rich water vapor carried by warm and humid airflow will condense, forming rain and snow weather. Due to the unusually long-term intersection of cold and warm air in this area, the rainy and snowy weather in southern China lasts for a long time.

Qi Xin joined forces to fight the snowstorm.

Common sense about snowstorms

Blizzard has brought great inconvenience to people's daily work and life. Then, how should we deal with this bad weather in our daily life to ensure personal safety and health? Expert tips, please pay attention to the following matters. (1) Understand the information, keep warm from the cold, and pay attention to safety.

Pay attention to the latest forecast and early warning information about blizzard; Prepare snow melting and sweeping tools and equipment; Reduce the number of vehicles going out; It is necessary to know the information about the suspension or closure of airports, expressway, docks and stations, and adjust travel plans in time; Store food and water; Stay away from unstable and unsafe buildings; It is necessary to prepare food and grass for livestock and resume grazing in the wild; Crops should take anti-freezing measures. Once a snowstorm happens, we should actively respond: do a good job of sweeping snow and melting snow on roads, and residents and shops should also actively cooperate, and "sweep the snow in front of the door"; When you go out, you should take measures to prevent cold and keep warm. In the severely frozen south, try not to wear hard-soled shoes and flat-soled shoes, and put old cotton socks on the shoe covers. This is a good way that many people have explored in this ice and snow disaster. Driving slowly, actively avoiding, keeping the distance between cars, stepping on the brakes less, obeying the traffic police's instructions and paying attention to road safety tips are the key points; Let the non-motor vehicle tires deflate a little and increase the friction between the tires and the road surface, which can also prevent slipping. If you encounter a snowstorm raid, in addition to the above precautions, you should pay special attention to stay away from billboards, temporary buildings, trees, telephone poles and high-voltage towers; When passing under a bridge, eaves, etc. You should watch carefully or simply take a detour because the ice falling from it is as lethal as a sword under the action of gravity acceleration. (2) Special attention must be paid to diet and nutrition when dealing with snowstorms.

Cold has many effects on human body. (1) affects the hormone regulation of the body and accelerates the metabolic decomposition of protein, fat and carbohydrate, especially fat; (2) affecting the digestive system of the body, making people increase their appetite and better digest and absorb; (3) It affects the urinary system of the body, and the corresponding increase in urination will increase the loss of minerals such as calcium, potassium and sodium. Therefore, these changes need to be reasonably regulated by corresponding nutrients to prevent the body from experiencing these physiological changes in a cold environment. Specifically, the following tasks should be completed:

① Increase the intake of warm food.

In the cold winter, people often feel uncomfortable because of the cold, and some people are particularly afraid of the cold because of the weak yang in their bodies. Therefore, in winter, it is necessary to use food with cold-proof function to keep warm and recuperate, so as to warm and nourish the whole body tissues, enhance physical fitness, promote metabolism, improve cold-proof ability, maintain the functional activities of body tissues, resist external evils and reduce the occurrence of diseases. Eat warm food in winter, such as mutton, dog meat, soft-shelled turtle, shrimp, pigeon, quail, sea cucumber, medlar, leek, walnut and glutinous rice. ② Increase the intake of heat-producing food.

Due to the cold climate in winter, the human body consumes more energy every day to adapt to the cold environment, so it is necessary to increase the intake of thermogenic nutrients. Thermogenic nutrients mainly refer to protein, fat and carbohydrates. Therefore, we should eat more foods rich in these three nutrients, especially increase the intake of fat. For example, we should pay attention to the intake of fat when eating meat dishes and put more cooking oil. ③ Supplement the necessary methionine.

Methionine can provide a series of methyl groups necessary to adapt to cold tolerance through transfer. The cold climate increases the excretion of creatine in human urine and accelerates the metabolism of fat. The heat released by the oxidation of creatine, fatty acids and phospholipids in mitochondria needs methyl. Therefore, we should eat more methionine-containing foods in winter, such as sesame seeds, sunflower seeds, dairy products, yeast, leafy vegetables and so on. ④ Eat more foods rich in vitamins.

Due to the cold climate, the oxidation heat production of human body is strengthened, and the vitamin metabolism of human body has also changed obviously. For example, increase the intake of vitamin A and enhance the cold tolerance of the human body. Increasing the intake of vitamin C can improve the adaptability of human body to cold, which has a good protective effect on blood vessels. Vitamin A mainly comes from animal liver, carrots, dark green vegetables and other foods. Vitamin C mainly comes from fresh fruits and vegetables. ⑤ Appropriate mineral supplement.

People's fear of cold is also related to the quality of minerals ingested by the body. For example, the content of calcium in the human body can directly affect the flexibility and excitability of the heart, blood vessels and muscles, and calcium supplementation can improve the cold resistance of the human body. Foods rich in calcium include milk, bean products and kelp. Salt is also very important for human body to keep out the cold, which can enhance the heat-producing function of human body. Therefore, in winter, it is mainly heavy taste and pungent heat, but it should not be too salty, and the daily salt intake should not exceed 6 grams at most. 6. Pay attention to hot food.

In order to adapt the human body to the cold environment, we should eat hot meals and hot dishes to absorb more energy to keep out the cold. You might as well arrange more hot soup on the dining table, which will not only increase your appetite, but also eliminate the cold feeling.