Why does freezing rain only appear in Guizhou and Hunan?

What is freezing rain? The rain that freezes immediately after raindrops collide with the ground or objects, planes and other things is called freezing rain. This kind of rain is supercooled water drops below 0℃ falling from the sky. When it comes into contact with branches, wires, hay or other ground objects, it will freeze into a smooth, crystal-clear ice shell on these objects, and sometimes it will freeze like an icicle. This kind of ice is also called "rainy season" in meteorology. Freezing rain mostly occurs in winter and early spring. In China, Guizhou Province is the region with more freezing rain, followed by Hunan, Jiangxi, Hubei, Henan, Anhui, Jiangsu, Shandong, Hebei, Shaanxi, Gansu and southern Liaoning. Among them, there are more mountains than plains, and the mountains are the highest. There was freezing rain in Bijie, Guizhou (2002 0 1-28 10:33). Bijie and Weining are located in the northwest of Guizhou Province with complex terrain. Every winter, after the arrival of strong cold air, the ground temperature drops below 0℃ Due to the influence of southwest airflow, the temperature at the altitude of1500-3000m is warmer and the water vapor is sufficient. When precipitation occurs, supercooled raindrops in the upper air melt into rain in the middle and lower layers. However, when raindrops reach the ground and the temperature is low, they will freeze on telephone poles or roads. It is called "freezing rain" in meteorology and "falling ice" in some places in southern China. After 65438+1October 18, due to the influence of cold air and warm and humid airflow, freezing rain or rain and snow weather often occurs in Bijie, Weining and other northwest areas of Guizhou. Highway traffic is blocked by ground icing, and traffic accidents increase accordingly. The fields are frozen, and crops such as green winter wheat are frozen to varying degrees. Freezing rain is a disaster, and farmers should especially strengthen anti-freezing measures. Freezing rain is a disastrous weather. After ice accumulates on the ground, it can crush power lines and telephone lines. Severe freezing rain will collapse houses, crush trees and bamboos, and freeze crops and vegetables. Because the ground is frozen, it has a great impact on traffic. Aircraft flying in clouds with cooling water droplets will accumulate ice on wings and propellers, causing accidents. 19841in the middle and late October, due to the influence of strong cold air, freezing rain occurred in many areas of Guizhou, Hunan, Jiangxi, Hubei and other provinces, resulting in broken wires and inverted poles. All the wired telephones in Guizhou province were interrupted, which seriously affected the communication work. The icing thickness of transmission lines in Hunan is more than 20 mm, and some high-voltage lines melt ice 5-6 times a day. Affected by freezing weather, 803 long-distance buses in Guiyang bus station stopped working, and 4 18 buses in rural areas stopped working intermittently. Several counties near Changsha, Hunan stopped 339 buses; Nearly 5 million bamboo trees were broken in Linwu and Zixing counties alone. In Guizhou, 10% of early bolting rape was damaged by freezing.