When clouds near the ground are lifted up by air currents, a large mass of supercooled water droplets are carried to the upper layer of the cloud. They freeze with existing ice particles in the upper layer, causing the volume of ice particles to become larger and larger.
When falling into the low cloud layer, the outer surface of the ice is covered with a layer of water, and at the same time is affected by strong and weak water currents that are constantly rising. The longer it is affected by air currents, the more water film the ice particles have, making the volume of the ice larger.
Ultimately, it will become a block of ice composed of many alternating clear and opaque layers. When ice particles are heavy enough and cannot be carried away by wind or air currents, they will fall to the ground, causing hail.
Why is there no hail in winter?
Small hailstones often melt before reaching the ground, but larger hailstones will fall to the ground and can cause major damage. Hail is most common in mid-latitudes in early summer.
Here, the lower atmosphere receives a lot of heat energy, so it is very hot, forming a column of hot, cold, unstable air. These are the conditions for the formation of convection phenomena and cumulonimbus clouds capable of causing hail.
Meanwhile, the upper atmosphere is still cold enough to support large ice particles that form and grow in clouds. This is why it can still hail in the summer, because the air on the ground can be warm, but in the sky it is still cold.
On the contrary, in winter, sunlight shines obliquely on the ground, so the heat generated is very weak, not causing strong convection. Meanwhile, the air is dry, making it difficult to create large cumulonimbus clouds. Even if cumulonimbus clouds are created, the upward convection current is not strong enough, the ice particle formation process cannot be performed. Therefore, in the cold season there is no hail.
Many people picked up large stones, 1-2 cm in diameter. (Photo: NVCC).
According to initial records, during the rain on June 14, hail concentrated in District 1 and District 4 was the size of a chopstick head. If the size is larger, the rain can cause punctures in corrugated iron roofs, crushing of crops or broken glass of houses and cars. Mr. Quyet further noted that large hailstones falling on people can easily cause dangerous injuries.
Updated: June 17, 2024 Znews