Twenty people died in convective weather.

The severe convective weather that caused heavy casualties in Shangqiu City of this province is a weather phenomenon called "squall line". When this weather phenomenon occurs, it is usually accompanied by thunderstorms, strong winds, hail and other processes, which are energy-intensive, destructive and difficult to predict.

Wang Jianguo, director of the Henan Meteorological Bureau, said that according to the preliminary analysis, it is a rare squall weather phenomenon that Shangqiu was so seriously affected. The so-called "squall line" is a narrow cloud band formed by many thunderstorm cell, which contains huge energy and is incompatible with the external weather system. At the intersection of squall lines, the wind direction turns sharply, the wind speed increases sharply, the air pressure rises sharply, and the temperature drops sharply, usually accompanied by violent weather processes such as lightning, rainstorm, gale and hail.

"This weather phenomenon has the characteristics of short formation time, fast development and fast movement, and it is difficult to forecast." Wang Jianguo said, "From the current monitoring and analysis, when a squall line appears, the possibility of a tornado in Shangqiu area, especially Yongcheng County, cannot be ruled out."

It is also known that before the above-mentioned severe convective weather, Henan Meteorological Observatory, Zhengzhou Meteorological Observatory and Shangqiu Meteorological Observatory all issued warning signals of lightning and gale to remind the local government to take precautions and advise the public to avoid outdoor activities as much as possible.