Summary of Snow Disasters
What is snow disaster?
Snow disaster is a natural phenomenon caused by a large amount of snow for a long time. It is a kind of animal husbandry meteorological disasters that often occur in pastoral areas of China ,mainly refers to the livestock farming areas which depend on natural grassland grazing, because of the excessive snowfall and snow cover in winter half year, the snow layer lasts for a long time, which affects the normal grazing activities of animal husbandry. Snow disaster is also called white disaster.
Snow disaster mainly occurs in stable snow areas and unstable snow mountain areas, occasionally in instantaneous snow areas.Snow disaster in pastoral areas of China mainly occur in grasslands of Inner Mongolia, northwest China and parts of the Qinghai-Tibet Plateau.
Types and indicators of snow disaster
(1) Types of snow cover
Snow disaster is caused by snow, according to the stability of snow cover, snow cover in China can be divided into five types:
Permanent snow accumulation above the snow line is greater than that of melting in the same year, and the snow does not melt all the year round.
The spatial distribution of stable snow cover (continuous snow cover) and the time of snow cover (more than 60 days) are relatively continuous seasonal snow cover.
Although unstable snow cover (discontinuous snow cover) falls every year, and the temperature is low, the snow cover is discontinuous in space, mostly in patchy distribution, the days of snow cover are 10 to 60 days in time, and intermittent.
Instantaneous snow cover mainly occurs in South and Southwest China, where the average temperature is relatively high,however, in the year when the monsoon is particularly strong, large-scale snowfall occurs due to cold wave or strong cold air invasion, but it melts quickly, resulting in short-term (usually no more than 10 days) snow cover on the surface.
There is no snow except for some mountains at high altitudes, no snow has fallen for many years.
(2) Index of snow disaster
Snow disaster mainly occurs in stable snow areas and unstable snow mountain areas, occasionally in instantaneous snow areas.People usually use the depth of snow cover on grasslands as the first sign of snow disaster.Because of the difference of grassland and the growth height of grass, the snow cover depth of snow disaster is different.
According to the analysis of observation and investigation data in Inner Mongolia and Xinjiang, the relationship between snowfall and the formation of snow disasters over the years is compared, and the indicators of snow disaster are as follows:the snowfall amount of light snow disaster in winter and spring is equal to more than 120% of the snowfall amount in the same period of the year;the snowfall in winter and spring is equal to more than 140% of the snowfall in the same period of the year;heavy snowfall in winter and spring is equivalent to more than 160% of the annual snowfall in the same period.
Snow disaster indicators can also be expressed by other physical quantities, such as snow depth, density, temperature, etc., however, the greatest advantage of these indicators is that they are easy to use and the data are easy to obtain.
(3) Classification of snow disaster
According to the formation conditions, distribution range and manifestation of snow disaster in China, snow disaster can be divided into three types:
Avalanches, snowdrift disasters (snowdrift) and snow disaster in pastoral areas.
According to the climatic law of snow disaster, it can be divided into two types: sudden type and persistent type.
(1) Sudden snowstorm occurs during or after a snowstorm, and keeps a relatively thick snow cover for several days, which poses a threat to livestock. This type is common in late autumn and spring with changeable climate.
(2) The snow cover thickness of the sustained snow disaster to endanger livestock gradually increases with the snowfall weather, the density increases gradually, and the stable snow cover lasts a long time. This type can last from the end of autumn to the next spring.
Of course, snow cover can play a positive defensive role in the overwintering heat preservation of forage grass, snow melting in dry season can increase soil moisture and promote the green growth of forage grass.
Snow is also the main source of water shortage or water-free winter and spring grassland, which can solve the drinking water problem of human and livestock.But too much and deep snow and too long duration make it difficult for livestock to graze, even unable to graze, thus forming a snow disaster.
Harm of snow disaster
The hazards of snow disaster are mainly as follows: causing casualties; destroying houses; destroying biodiversity, causing casualties of animals and plants, such as piglets and other livestock are also prone to death from frostbite;destroying or affecting lifeline projects such as transportation, communication and transmission lines, there have been large-scale blackouts caused by heavy snow in North China.
A large amount of snow can collapse the greenhouse, causing frost damage to vegetables, snow can also shield room temperature and greenhouse light, which has a greater impact on vegetable production; snow often accompanied by strong wind cooling, temperature drops sharply after snow, if preventive measures are not taken in time, often resulting in low temperature freezing damage.
Snow disasters mainly occur in Inner Mongolia grassland, northwest China and parts of the Qinghai-Tibet Plateau.At the turn of winter and spring from 1992 to 1993, heavy snow fell successively in parts of Inner Mongolia, Qinghai, Tibet and Gansu provinces and autonomous regions, affecting more than 300 million mu of grasslands, 1.1 million people and 1 million livestock.
Frozen rain and snow in southern China since January 10, 2008 is a very rare snow disaster. 22 provinces (regions and cities) such as Zhejiang, Jiangsu, Anhui, Jiangxi, Henan, Hubei, Hunan, Guangdong, Guangxi, Chongqing, Sichuan, Guizhou, Yunnan, Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang have been affected by low temperature, snow and ice disasters.
129 people died in the snow disaster, 4 people were missing, 1.66 million people were relocated in emergency; 217 million mu of crops were damaged and 3076 mu of no harvest; nearly 340 million mu of forests were damaged; 485,000 houses collapsed and 168,600 houses damaged, with direct economic losses reaching 151.65 billion yuan.
It is worth mentioning that the 2008 snow disaster is still fresh in the memory of all Chinese people. Many people may never forget the snow in their lifetime;Shaoguan Section of Beijing-Zhuhai Expressway was closed and the ice and snow disaster was serious;Guiyang reproduced the miracle of ice falls;Passengers were blocked for ten days and ten nights in Lechang, Hunan and Shaoguan respectively by the snowstorm by bus......Near the Spring Festival, snowstorms suddenly fell in most parts of the middle and lower reaches of the Yangtze River, and large snowflakes covered the land in the south.The transmission tower was crushed by ice accumulated on the brackets, power supply in many cities was interrupted and the city was dark.Water pipes in disaster-stricken cities were frozen due to low temperatures, people were seriously short of water for daily use,only could rely on fire trucks to transport drinking water for residents.Expressways, railways and airports were covered with thick ice, and all kinds of vehicles could not operate normally, at the peak of spring transportation, a large number of passengers who were ready to go home for the Spring Festival were stranded at stations and airports.
The dangerous climate of the ice and snow had nearly collapsed tens of millions of private car owners and those who were preparing to drive and return home by car; high-speed road accidents, traffic jams, vehicle damage......
The arrival of this snow disaster was mainly due to the abnormal large-scale snowfall and severe cold climate in some areas under the background of global warming.This heavy snow, which has not been seen for 50 years, has caused great disasters in the southern part of China with great losses to the social economy and people's lives and property.
Response measures of snow disaster
Warning signals of blizzard
Warning signals of blizzard are divided into four levels, which are blue, yellow, orange and red, respectively. Shown in table 6-6.
Prevention measures of blizzard
Patrol roads and repair them in time.When blizzard weather occurs, departments such as transportation, railway, power and communications should strengthen patrols and close icy roads when necessary, once snow breaks down roads, railways or lines are found, timely repairs are ensured.
Keep warm and skid-proof when go out.Facing blizzard weather, pedestrians should pay attention to cold and skid resistance, choose shoes with good skid resistance when going on the road, and not wear shoes with high heels or hard plastic soles; when vehicles go out, necessary anti-skid measures should be taken to install anti-skid chains for the vehicle.
Blizzard raging with reinforcement and protection.Before or during the blizzard, the temporary structures concerned should be reinforced and protected in time to avoid being crushed by snow or even causing casualties.
(1) Measures to deal with blizzard disasters
Heavy snow disasters occur almost every year in our country, which often lead to the isolation of people and animals from the outside world, and suffer disasters due to cold and hunger, so we should take preventive and emergency measures.
①Preparatory measures for preventing blizzard disasters.Before winter comes, we should prepare enough food, feed, fuel and clothing;reinforced housing;familiar with living environment and setting good landmarks;prepare call signals, snow supplies and medicines;keep warm, avoid frostbite, don't touch cold objects;wear snow-blind glasses when going out.
Prepare a snow shovel, flashlight and battery-operated radio at home or in the car; store emergency water and perishable food;close the outside tap to avoid bursting and flooding;put the special medicine and medical method manual in your room where you can easily get it;buy a kerosene lamp or heater that can be safely used indoors; store some salt, hay and sand;make the house population unobstructed.
Fill your car with gas in case you need to drive to a warmer place and check the car's antifreeze again.
② Physical energy accumulation during blizzard.When a blizzard occurs, you should stay indoors and try to keep yourself warm.Don't shovel snow, trolley, or try to walk long distances in the snow, excessive sweating can make you cold or hypothermia in extreme cold conditions.For the elderly or susceptible, sudden exertion can damage the heart.Eat more high-energy foods, such as oats, dried fruits, bread and peanut butter, and plenty of hot drinks to maintain body temperature and fluid intake.
(2) How to deal with the sudden blizzard?
①Stay indoors as much as possible and don't go out.
②If you are outdoors, stay away from billboards,temporary structures and old trees to avoid damage.When passing under bridges, eaves and other places, careful observation or bypass should be made to avoid injuries caused by melting ice.
③Non-motor vehicles should give tires a small amount of deflation to increase the friction between tires and road surface.
④Obey the traffic police's command and traffic guidance arrangements.
⑤Attention should be paid to listening to weather forecast and traffic information so as to avoid delays due to the suspension or closure of airports, expressways and ferry terminals.
⑥Drive slowly and keep a distance from the front car.Vehicles should slow down before turning to avoid braking. Conditions to install anti-skid chains, wear sunglasses.
⑦After the occurrence of traffic accidents, clear signs should be set at the rear of the scene to prevent the occurrence of serial crashes.
⑧ If there is a power failure accident, the power department should report it to the power department in time for prompt treatment.
(3) How to deal with snow disaster?
①Attention should be paid to cold and warmth preservation, old, weak, sick and young people should not go out.
②Don't wear hard or smooth soles when you walk.,cyclists can properly ventilate tires.
③Close doors and windows and fasten outdoor structures.
④ Should evacuate quickly in case of a snowstorm if in a dilapidated house.
⑤Households using stoves for heating should be on guard against gas poisoning.
(4) Prevent livestock from frostbite.
①Keep fat by feeding intensive materials to livestock.
②Clean up the feces in the fence in time, change and sun the mattress frequently, and keep the house clean and warm.
③Prevent cold wind from entering human and livestock houses.
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