What does the weather symbol composed of three curves mean?

The three arc icons in the weather forecast are blowing sand. Sand blowing is caused by local or nearby dust being blown by the wind. Visibility dropped significantly, and the sky was cloudy and yellow when it appeared. The north is easy to appear in spring. The wind is strong in sand-blowing weather, which affects the visibility between 1 km and1km.

Dust weather is a disastrous weather phenomenon in northern China (especially in northwest China) in spring. This kind of weather can be divided into three levels according to the horizontal visibility, namely floating dust, sand blowing and sandstorm.

Extended data: Sand blowing and sandstorm are both caused by the violent activity of large air flow, which brings up the surface dust in a specific area. Its * * * characteristics are obviously reduced visibility and cloudy sky. It mostly happens when cold air passes through the border in northern spring, but the difference is that the visibility affected by sand blowing weather is between 1 km and 10 km. The visibility of sandstorm and windy weather is even less than 1 km.

As a kind of high-intensity sandstorm disaster, sandstorm can't happen in all windy places, but only in those areas with dry climate and sparse vegetation. Sandstorms mostly occur in April-May every year.

Take the northwest of China as an example. At this time of year, the Hawaiian high is formed in the Pacific Ocean, the Indian low is formed in the Asian continent, and the strong south wind blows from the ocean to the land. The Mongolian high, which controls the mainland, began to move westward and northward, where cold and warm air currents met, and the heavy Siberian cold current came rapidly from west to east, often forming strong winds. The wind force that forms sandstorms is generally above 8, and the wind speed is about 25 meters per second. In addition, the formation of sandstorms requires sufficient sand sources, and dust can be blown off the ground by the wind.