Right now we are witnessing truly extreme climatic phenomena in our country. Just consider the recent flood, tornado, and giant hail in Sochi.
In the photos «making the rounds» on social media, you can see hailstones the size of balls. We explain why they can reach such sizes.
Krasnodar Region underwater: what is happening on the streets of Sochi and Adler Hail forms during severe thunderstorms, but to understand how it develops, we need to consider some important factors:
Formation
It all begins with the presence of particles suspended in the atmosphere, known as condensation nuclei. These can be dust, pollen, or any other suspended material. When the air is highly humid, water condenses around these nuclei and forms tiny grains of ice.
Growth
The newly formed ice grains are carried up and down within the cloud by strong air currents. During this process, the ice layers grow as layers of frozen water accumulate around the nucleus.
Coalescence
As the ice grains fall through the cloud, they can come into contact with other ice particles and water droplets that have not yet frozen. This process of merging causes the hailstones to grow further.
Strong updrafts
Hail reaches its largest size when it is lifted within the cloud by «updrafts», strong upward winds. They push the hail upward, where it meets even more water droplets freezing around the nucleus, increasing the size of the hailstones.
Downdraft
Hail reaches the ground when the force of the updrafts can no longer support its weight, and gravity causes it to fall. When the downdraft of air is especially strong, it can cause hailstones to grow to very large sizes before they fall to the ground.
Simply put, large hail forms when the ice grains inside a cloud become very large and are pushed up by strong air currents, allowing them to accumulate more ice before they fall to the ground.
