Sandstorms are divided into several grades.

There are several levels of sandstorms, and we will find that there are sandstorms in many cities, and sandstorm weather is a general term for a weather phenomenon that the wind pulls dust into the air and makes the air turbid. Let's take a look at the level of sandstorms and related information.

Sandstorms are divided into several grades. The intensity of sandstorm is divided into four levels.

1, 4 ≤ wind speed ≤ 6,500m ≤ visibility ≤ 1000m, which is called weak sandstorm;

2, 6 ≤ wind speed ≤ 8,200 meters ≤ visibility ≤500 meters, which is called medium-intensity sandstorm;

3, the wind speed is greater than 9, and the visibility below 50 meters is less than 200 meters, which is called a strong sandstorm;

4. When it reaches its maximum intensity (instantaneous maximum wind speed ≥ 25m/s, visibility ≤ 50m, or even reduced to 0m), it is called particularly strong sandstorm (or black storm, commonly known as? Black Wind).

Dust weather processes are divided into four categories.

1. Floating dust weather process: In the same weather process and at the same observation time, floating dust weather occurred in five or more countries in China weather forecast area;

2. Sand-blowing weather process: In the same weather process, sand-blowing weather occurred in five or more countries in China weather forecast area at the same observation time;

3. Sandstorm weather process: In the same weather process, sandstorms occurred in three or more countries in China gas forecast area at the same observation time;

4. Strong sandstorm weather process: In the same weather process, three or more countries in China weather forecast area basically (quasi) stood at the same observation time, and strong sandstorm weather occurred.

Sandstorm weather is one of the main disastrous weather affecting northern China, especially severe sandstorm will destroy human living environment and endanger people's health. In addition to basic preventive work, it is also necessary to strengthen fences, scaffolding, temporary structures and other structures that are easily blown by the wind, and properly place outdoor items that are easily affected by sandstorms. When it is predicted that sandstorm weather may occur within 24 hours, or sandstorm weather has appeared and may continue, meteorological departments at all levels shall issue a yellow warning signal for sandstorm.

Sandstorms are divided into several grades: 2 1. Floating dust: a weather phenomenon in which dust and fine sand float evenly in the air, making the horizontal visibility less than 10 km;

The so-called floating dust weather process refers to the occurrence of floating dust weather in five or more countries in the weather forecast area of China at the same observation time in the same weather process;

2. Sand blowing: the wind blows up the dust on the ground, making the air quite turbid, and the horizontal visibility is within 1 km to1km;

The so-called sand-blowing weather process refers to the occurrence of sand-blowing weather in five or more countries in China's weather forecast area at the same weather process and observation time;

3. Sandstorm: a weather phenomenon in which strong winds blow up a lot of dust on the ground, making the air very turbid and the horizontal visibility is less than 1 km;

The sandstorm weather process refers to the sandstorm weather in three or more countries in the weather forecast area of China at the same observation time;

4. Strong sandstorm: a weather phenomenon in which strong winds blow up dust on the ground, making the air very turbid and the horizontal visibility is less than 500 meters.

Strong sandstorm weather process: In the same weather process, more than three countries in China's weather forecast area basically (quasi) stand at the same observation time and have strong sandstorms.

Take these measures in the face of sandstorms.

1, indoor doors and windows should be closed in time, and doors and windows can be sealed with tape if necessary. Humidifier, sprinkler or wet mop should be used indoors to clean the dust and keep the air humidity appropriate.

2. When the sandstorm is about to happen or has already happened, residents should try to reduce going out. Minors should not go out. If you need to go out because of special circumstances, you should be accompanied by an adult.

3. If it is necessary to go out, residents should bring dust-proof articles such as masks or scarves. Myopia patients should not wear contact lenses to avoid eye inflammation and the damage of sandstorm to respiratory tract and eyes.

4. When the sandstorm happens, it is not suitable for outdoor sports and leisure activities. All outdoor collective activities should be stopped immediately, and people should be evacuated to a safe place to avoid.

5. In dusty weather, pedestrians should be cautious when riding bicycles, and should slow down. If the visibility is poor and the line of sight is not good, it is necessary to rely on the roadside. Pedestrians should pay attention to safety when crossing the road. Don't cross the road rashly.

In what season does the dusty weather mainly occur?

Sandstorm weather mainly occurs in late spring and early summer. This is because there is little precipitation in winter and spring in arid areas, the surface is unusually dry and loose, and the wind erosion resistance is very weak. When there is a strong wind blowing, a lot of dust will be involved in the air, forming sandstorm weather.

Sandstorms are divided into several grades. 3. The main hazards of sandstorm weather.

1, ecological environment deterioration

When sandstorms occur, dust and floating dust carried by strong winds are everywhere, and the number of people passing through areas with air turbidity, choking nose and eyes, respiratory tract and other diseases increases. For example, during the severe sandstorm in Jinchang on May 5, 1993, the dust content in outdoor air was 10 16 mm/cm3, and the dust content in indoor air was 80 mm/cm3, which was 40 times higher than the national standard for dust content in living quarters.

2. Production and life are affected.

A lot of dust carried by sandstorm weather blocked the sun, and the weather was gloomy, which led to the decrease of solar radiation. A few hours to ten hours of poor visibility can easily make people feel depressed and reduce the efficiency of work and study. In light cases, a large number of livestock can be infected with respiratory and gastrointestinal diseases, and in severe cases, a large number of "spring-deficient" livestock will die, and fertile soil, seeds and seedlings in farmland will be scraped away. Sandstorm will also aggravate the wind erosion and desertification of the surface soil, cover thick dust on the leaves of plants, affect normal photosynthesis and cause crop yield reduction.

3. Loss of life and property

1On May 5, 1993, severe sandstorms occurred in Jinchang, Wei Wu, Minqin, Baiyin and other cities in Gansu Province, affecting 2,535,500 mu of farmland, losing 42,800 trees, resulting in a direct economic loss of 236 million yuan, 50 people died and 0/53 people were seriously injured. On April 12, 2000, strong sandstorms occurred in Yongchang, Jinchang, Wei Wu and Minqin. According to incomplete statistics, the direct economic losses of Jinchang and Wei Wu alone amounted to15.34 million yuan.

4, traffic safety (plane, car and other traffic accidents)

Sandstorm weather often affects traffic safety, causing planes to fail to take off or land normally, and making cars and train carriages rupture, stop or derail.