What is the standard of heavy snow?

What is the standard of heavy snow? We know the weather through the weather forecast every day, and there are certain standards to judge each kind of weather. Snowfall is divided into four levels, namely: light snow, medium snow, heavy snow and blizzard. So what is the standard of heavy snow? Let's take a look.

The standard of heavy snow is the classification standard of several millimeters of snowfall 1.

Snowfall grade standard: 24-hour precipitation is used as the division standard, where the precipitation is 0, 1 ~ 2,4 mm for light snow,1,3 ~ 7 mm for small to medium snow, 2,5 ~ 4,9 mm for medium snow, 3,8 ~ 7,4 mm for moderate to heavy snow, reaching 5,0-. The classification standard of snowfall is based on the precipitation of 12 hours, where 0,0 1 ~ 0,9mm of precipitation is light snow, 0,5 ~1,9mm is small to medium snow,1,0 ~ 2,9mm is medium snow and 2,0 ~ 4.

Blizzard Blizzard warning signal is divided into four levels: blue, yellow, orange and red.

First, the meaning of blue warning

Standard:/kloc-The snowfall will reach more than 4 mm within 0/2 hours, or it has reached more than 4 mm and the snowfall continues, which may have an impact on traffic or agriculture and animal husbandry.

Defensive measures:

1, the government and relevant departments shall prepare for snow disaster and freezing damage according to their duties;

2, transportation, railway, electric power, communications and other departments should carry out road, railway, line inspection and maintenance, do a good job of 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, agricultural and pastoral areas and aquaculture to reserve feed, do a good job of snow and antifreeze;

5. Reinforce temporary structures that are easily crushed by snow, such as scaffolding.

Second, the meaning of yellow warning

/kloc-within 0/2 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.

Defensive measures:

1, the government and relevant departments shall, in accordance with their duties, implement measures to prevent snowstorms and freezing damage;

2, transportation, railway, electric power, communications and other departments should strengthen the inspection and maintenance of roads, railways and lines, do a good job of 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, agricultural and pastoral areas and aquaculture should prepare enough feed to prevent snowstorms and freezing damage;

5. Reinforce temporary structures that are easily crushed by snow, such as scaffolding.

Third, the meaning of orange warning

Within 6 hours, the snowfall will reach 10 mm or above, or it has reached 10 mm and the snowfall continues, which may or has had a great impact on traffic or agriculture and animal husbandry.

Defensive measures:

1, the government and relevant departments shall, in accordance with their duties, do a good job in emergency prevention of snow disasters and freezing injuries;

2, transportation, railway, electric power, communications and other departments should strengthen the inspection and maintenance of roads, railways and lines, do a good job of 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 outdoor livestock into the shed for food.

Fourth, the meaning of red warning.

Within 6 hours, the snowfall will reach 15 mm or above, or it has reached 15 mm and the snowfall continues, which may or has had a great impact on traffic or agriculture and animal husbandry.

Defensive measures:

1, the government and relevant departments shall, in accordance with their duties, do a good job in emergency rescue to deal with snowstorms and freezing injuries;

2, when necessary, suspend classes, business (except special industries);

3, when necessary, the plane suspended take-off and landing, the train stopped running, the highway was temporarily closed;

4. Do a good job in disaster relief work in pastoral areas.

Release method

The competent meteorological department of the State Council is responsible for the issuance, cancellation and dissemination of national early warning signals. The local competent meteorological departments at all levels shall be responsible for the administration of the release, cancellation and dissemination of early warning signals within their respective administrative areas. Other relevant departments shall, in accordance with their duties, cooperate with the competent meteorological departments in the release and dissemination of early warning signals.

Local people's governments at all levels should strengthen the infrastructure construction of early warning signals, establish smooth and effective channels for the release and dissemination of early warning information, expand the coverage of early warning information, and organize relevant departments to establish emergency mechanisms and systems for meteorological disasters.

Management units of schools, airports, ports, stations, highways, tourist attractions and other crowded public places shall set up or use electronic display devices and other facilities to spread early warning signals. The state protects the special transmission facilities for early warning signals according to law, and no organization or individual may occupy, damage or move them without authorization.

Early warning signals shall be issued uniformly. Meteorological offices and stations subordinate to the competent meteorological departments at all levels shall issue early warning signals in accordance with the release authority and business processes, and indicate the early warning areas of meteorological disasters. Release authority and business process shall be formulated separately by the competent meteorological department of the State Council. No other organization or individual may issue an early warning signal to the society.

The standard of heavy snow is the corresponding relationship between the snowfall of several millimeters and the depth of snow: generally speaking, the depth of snow in the northern region can reach 8- 10 mm and that in the southern region can reach 6-8 mm without melting after snowfall.

The role and influence of snowfall

For crops

Snow is beneficial to the growth and development of crops. Snow is a kind of material with good heat preservation effect, which can protect plants from frostbite in cold winter. The melting of snow water in the next spring can provide a good water supply for vegetation. The power of nature is definitely not a coincidence. Because of the poor thermal conductivity of snow, covering the soil surface with a layer of snow can reduce the diffusion of soil heat and prevent the cold from invading the snow surface.

Therefore, crops protected by snow can survive the winter safely. Snow can also store water for crops. In addition, snow can enhance soil fertility. According to the determination, every 1 liter of snow water contains about 7 or 5 grams of nitride. Snow water permeates the soil, which is equivalent to applying nitrogen fertilizer once.

Feeding livestock and poultry with snow water and irrigating crops can obtain obvious benefits.

At the same time, sufficient snow and water in winter can not only alleviate the drought in that year, but also provide favorable conditions for timely sowing and full seedling growth of spring-sown crops in the coming year.

human health

Why does snow have such strange functions? Because snow water contains less heavy water than ordinary water 1/4. Heavy water will seriously inhibit the life process of living things. It has been experimented that fish will soon die in water containing 30%-50% heavy water.

The most basic condition for the formation of rain and snow is the existence of "condensation nuclei" in the atmosphere, and solid impurities such as dust, coal particles and minerals in the atmosphere are the most ideal condensation nuclei.

If meteorological factors such as water vapor and temperature in the air reach certain conditions, water vapor will condense into snowflakes around these condensation nuclei. Therefore, snowflakes can clean many pollutants in the air, and the air is particularly fresh after a heavy snow.

For rural people, snow adds a quilt to crops, which is wet and loose, indicating a bumper harvest in the coming year. For city people, snow only improves the air quality and increases the fun of playing.

According to the measurement, the density of new snow is generally 0,05-0 and 10g per cubic centimeter. Therefore, the reflectivity of ground snow to sound waves is extremely low, which can absorb a lot of sound waves and help reduce noise.

Thermal insulation function

Snow is like a wonderful carpet, covering the earth, so that the temperature of the ground will not drop too low because of the cold in winter. This heat preservation effect of snow is inseparable from its own characteristics.

As we all know, it is warm to wear cotton-padded jacket in winter, because the porosity of cotton is very high, and the pores of cotton are filled with a lot of air, which has poor thermal conductivity. This layer of air prevents the heat of human body from spreading outward. This is because air is a bad conductor.

As we know, any object itself can transfer heat, and this property of transferring heat is called the thermal conductivity of the object. Among several common substances in nature, air has the worst thermal conductivity. Therefore, the more air an object contains, the worse its thermal conductivity.

The snow covering the breast of the earth is very similar to cotton, and the porosity between snowflakes is very high. It is this layer of air that drills into the pores of the snow to protect the ground temperature from falling very low. Of course, the thermal insulation function of snow changes with the density at any time.

It's like wearing a new cotton-padded jacket, which is especially warm, and the old cotton-padded jacket is not very warm. The density of fresh snow is low, and there is a lot of air stored in it, so the heat preservation effect is particularly strong. Chen Xue is like an old cotton-padded jacket, with high density and weak heat preservation effect, because there is less air stored in it.

As a water resource

When the city is threatened by snowfall, the "urban secondary disasters" related to snowfall gradually appear, and the losses caused by snowfall become increasingly prominent, which seriously affects the normal operation of urban economic life.

In addition, the development of urbanization has also caused the shortage of water resources in many cities, especially in China, where there is less precipitation in winter, and the problem of urban water shortage is more prominent. Urban snowfall plays an extremely important role in alleviating and supplementing the shortage of urban water resources in winter and improving and protecting the ecological environment.

The standard of heavy snow is a few millimeters of light snow: when it snows, the horizontal visual distance is equal to or greater than 1000m, the ground snow depth is less than 3cm, the 24-hour precipitation level, and the snowfall is between 0.1~ 2.4 mm. ..

Snow: refers to the horizontal visual distance between 500 ~ 1000m when it snows, the depth of snow on the ground is 3 ~ 5cm, and the snowfall in 24 hours is 2.5 ~ 4.9 mm. ..

Heavy snow: refers to the poor visibility when it snows, the horizontal visual distance is less than 500 meters, the depth of snow on the ground is equal to or greater than 5 cm, and the snowfall in 24 hours reaches 5.0 ~ 9.9 mm.

If there is snowfall without forming snow, it is generally called "sporadic light snow".

When the snowfall reaches 10.0 ~ 19.9 mm in 24 hours, it is a blizzard, 20.0 ~ 29.9 mm is a blizzard, and more than 30.0 mm is a blizzard.

What are the standards of light snow, heavy snow, heavy snow and heavy snow? Meteorology has strict regulations on the amount of snowfall, which is completely different from the standard of rainfall. Snow quantity is a measure measured by meteorological observers after melting the collected snow in a certain standard container. Meteorologically speaking, the amount of snowfall ...

How is the grade of snow divided?

Snowfall is divided into four grades: light snow, medium snow, heavy snow and blizzard. Light snow: 0. 1~2.4 mm/day; Medium snow: 2.5~4.9 mm/day; Heavy snow: 5.0~9.9 mm/day; Blizzard:10mm/day or more.

How to define snowfall?

The precipitation of snow is measured by the amount of snow: the amount of snow is a measure measured by meteorological observers after melting the collected snow in a certain standard container.