Hail is formed when raindrops pass through a belt of cold air on their way to earth. This belt of cold air causes the raindrops to freeze into small blocks of ice. The formation of hail requires the presence of cumulonimbus or other convective clouds with strong updrafts. The air turbulence that accompanies thunderstorms aids the formation of hailstones. The water that goes into the formation of hailstones is super cooled water, that is to say, it is at a temperature below freezing point but still in the form of a liquid. Hailstones start falling when they become too heavy to be supported by air currents.
Features of Hailstorm
- Hailstorm wind moves with a speed of 70 miles per hour.
- The air current associated with hailstorm is highly powerful.
- Hailstorm is frequently observed midlatitudes. It happens mostly near mountain range as the slopes in mountains push the horizontal air currents in the upward direction.
- Biggest hailstone recorded so far was found in Kansas in the year 1928. It was like a huge ball with a weight of 758 grams.
- Hailstorms that carry heavy hailstones with it cause severe damage to living beings and property. Giant-sized hailstones falling with high speed can even cause death.
Facts of Hailstorm
The following are some interesting facts about hailstorms.
- Hailstorms, though destructive in nature are a form of precipitation, like snow and rain, and are hence unavoidable.
- The ice ball that falls down from the sky with a great force, during a hailstorm, is known as a ‘hailstone’. An average ‘hailstone’ can have any diameter between 5 to 150 millimeters.
- The hailstorms are not exactly storms, but are a side effect of a much bigger storm, the thunderstorm. In fact, hailstorms originate from thunderclouds.
- The hail originates from thunderclouds that are also known as Cumulonimbus clouds.
- Weather forecast agencies and departments, newspapers, TV channels and other media organizations, do not refer to the actual size of a hailstones in millimeters, while reporting the severity of a hailstorm. The objects of comparison that are often used are, coins like, cents, dimes or dollars. Some other objects also include marbles, golf balls and peas. For Example: Last night’s hailstorm, was not very severe and the size of hail was equivalent to that of a ‘pea’.
One of the most sever and dangerous hailstorms that occurred in the modern times fell on the night of 7th of July, 2009, in a suburb of New York, known as Yonkers. The storm left behind a two inches thick layer of snow and caused a flash flood and also one mud slide.
- The largest of all hailstorms was recorded in Aurora, Nebraska, United States in 2003.
- Another very big hailstorm occurred early in the 9th century, in Roopkund, India. It is supposed to be one of the earliest officially recorded hailstorms.
- In Colorado, United States, the citizens have a ‘hailstorm season’, that lasts from March to October, every year.
- Hailstorms have rarely lasted for more than 15 minutes. The median of the time span of these storms is about 6 minutes.
- According to the climate departments of governments all over the world, hailstones must have at least ¾ inch of diameter to become severe, and cause a substantial amount of damage.
- Hailstorms usually occur mostly in mountainous regions than the regions with a lower temperature.