How is hail formed? What are the necessary conditions for the formation of hail?

Hail is a common weather phenomenon in summer, but now most parts of China have just entered spring. Why is there hail? In fact, the reason of more hail in summer is related to its formation conditions. The conditions for hail formation in summer are relatively sufficient, so it is more common in summer. But this does not mean that other seasons have disappeared. As long as the conditions are met, hail weather may happen at any time. Let's learn about the causes of hail together.

hail

First of all, understand the meaning of hail. The so-called hail is that water vapor condenses into clouds and will liquefy when it meets cold air. Then when the temperature is lower, the water vapor will turn into rain or snow. The temperature drops too much, and the condensed ice is larger. This is hail. By the way, the relative humidity here should reach 100%. In this sense, we can even get the conditions and process of hail formation with water vapor, strong updraft, temperature difference and nodules. Why is it easy to hail in summer? Summer is rich in precipitation and strong sunshine, so it will produce a lot of water vapor and strong updraft. Secondly, when water vapor rises to a certain extent, it will encounter cold. This is the temperature difference. Lower temperature will turn water vapor into clouds and condensation nuclei, which will lead to hail.

Formation of hail

Of course, these conditions are not enough. Because there may be raindrops or small hail cores. Because this hail core still needs to grow, it needs to be accumulated into a large enough and complete hail. After the formation of hail nuclei, water should be enough to gather a large number of ice crystals and hail nuclei and become hail. When the hail is big enough, the updraft will become a little weak, unable to support it, and it will land. This is what we call hail. Don't do this. The process of ascending-cooling-condensing-descending seems simple, but in fact many conditions need certain standards. For example, how much water should there be and how low the cold temperature should be if it rises.

Won't it come out when it freezes in winter? Why does it hail in summer and autumn?

It takes a condition to produce hail. It must be strong convective weather. We all know that the temperature will drop with the elevation. For example, the snow line in Tianshan is about 3500 ~ 4000 meters. In other words, beyond this height, there may be snow that does not melt all the year round, and the clouds are obviously above this height, so it is very normal for ice crystals to exist in high-altitude cumulonimbus clouds, so why does it rain most of the time?

1. If there is no strong convective weather, the condensation nuclei formed by cumulonimbus clouds will turn into water droplets falling off or pushed down by convective weather, repeatedly forming larger raindrops. Such as rain or rainstorm in Mao Mao! Or, if there is no condensation nucleus, the small ice crystals formed at a lower temperature will melt into water droplets again during the falling process.

2. If the thunderstorm cloud has strong convective weather, the ice crystals formed by the thunderstorm cloud at high altitude will be repeatedly pushed into the sky by the updraft during the falling process, and water droplets will be added continuously in the process, which will re-condense into large ice cubes, which is the origin of hail. The stronger the updraft, the greater the hail may be!

How to prevent hail attack?

Close doors and windows, and place outdoor items that are easily affected by hail and strong wind. It is best to park the car in the garage, and of course it is best to insure the car in advance.

Residents should not go out casually and ensure that the elderly and children stay at home.

Kindergarten children and school students should be arranged in the classroom and stop outdoor activities.

Outdoor workers must stop working, so they should immediately enter the room for temporary refuge.

Field personnel should not enter isolated huts, sentry boxes and other buildings, nor should they avoid hail from high-rise chimneys, telephone poles and trees. Try to find a strong place to hide. Especially when it thunders.

While preparing for hail suppression, we should also prepare for lightning protection.