10 things you may not know about hail

Hail is one of the most dangerous natural phenomena on earth. With thunderstorms, extremely strong whirlwinds plus the possibility of damage from hail stones, both houses, trees and people are harmed. Hidden in the hail, there are many secrets that you may not know.

1. People often think hail will appear in the winter but the truth is that summer is the most likely to happen hail. The nature of hail is due to instability in the air when two cold and hot air streams meet. So in the summer when there are more hot air pillars rich in energy, it will be easier to create hail storms.

Hidden in the hail, there are many secrets that you may not know.

2. In the largest clouds (known as rain clouds or cumulonimbus clouds) , the air in the upper part of the cloud has colder temperatures and the water vapor here forms small ice particles. These ice particles will move down to the lower part and then return to the upper part of the cloud, repeated, each time the layer of ice around the ice is thicker. Until heavy enough these stones will fall to the ground and create hail.

3. The condition for a cloud to produce hail is that the top part of the cloud must be below -20 degrees Celsius and most of the cloud is below freezing (0 degrees Celsius). Combining with thunderstorms will form big hailstones.

4. Hailstone is usually 5 - 200mm in diameter, can be as small as a pea, or as big as an egg or even as large as a grapefruit. Each hailstone can weigh up to 1kg and if some particles stick together, they can form 4kg blocks.

When cutting double hail beads we will see the ice circle.

5. Hailstone falls at a very fast speed so it does not melt before touching the ground, even in the middle of hot summer days. A hailstone the size of a tennis ball (about 75mm in diameter), weighing 150 grams can fall at a speed of 160km / h. This explains why plants and houses were severely destroyed after only a few minutes of brief hail.

6. When you cut double hailstone, you can see things like rings made from ice. Some "ice rings" are milky white, others are transparent. The layers of "ice rings" intertwined, count how many layers are the number of up and down moves of hailstones on top of the cloud.

7. In some cold climates like England, there are frequent hail in winter, this is not the hail we are talking about. Local people call these rains Graupel . This is a kind of soft hail , formed when the slow water droplets combine a layer of ice or salt mist to form raindrops. Soft hail is created similar to snow and does not harm like hard hail.

Hail is a very dangerous natural phenomenon.

8. The largest hailstone recorded in the UK is in Horsham, West Sussex area on September 5, 1958 weighing 142 grams.

9. Meanwhile in the US, the largest hailstone weighs up to 0.88kg and has a diameter of up to 20cm. This raindrop appears in hail on July 23, 2010 in Vivian, South Dakota.

10. Hail not only causes damage to property and crops, but also can kill people. In 1888, there were nearly 250 Indians killed by hail.