From June 11 to 12, heavy rain, hail and other severe convective weather occurred in many places in North China, especially in Beijing, Tianjin and Hebei. Since yesterday afternoon, has experienced a sudden hail attack. Today, according to @ cctv.com, at present, China has entered a high incidence period of hail, so how much is the destructive power of hail?
According to experts, when an egg sized hail (about 30g) falls to the ground from 1000 meters high, is equivalent to a 3kg object falling from a height of about 10 meters, which is almost equivalent to throwing a flower pot with soil from a place three stories high, hitting people or cars. If we encounter hail outdoors, several "flower pots" will fall from the sky.
It should be noted that the above conversion is the estimation result without considering air resistance, updraft movement and other factors. During the falling process, hail will inevitably be affected by air resistance and other factors, and its lethality may decline.
It is understood that hail often occurs at the turn of spring and summer, and it is also common in June. The formation of hail requires three main conditions. First, the atmosphere must have unstable stratification. Second, the cloud cluster must have the freezing temperature of large water droplets. Third, there must be strong vertical wind, which is conducive to the continuous condensation of raindrops.
In addition, hail has the following characteristics: strong locality, with an impact range of tens of meters to several kilometers** The duration is short, generally 2-10 minutes, and a few more than half an hour.