Hailstones that fell over a 15 minute period are seen August 3, 2004 in Alton, Hampshire, England.
Photo by Julian Herbert/Getty Images
Hail is a form of precipitation that falls from the sky as pellets of ice. The pellets can range in size from small pea-sized pellets, to hailstones as large as grapefruits. Hail is especially damaging to crops. In the central US, where many hail storms are reported each year, delicate wheats and other crops are often ruined. Annually, hail can cause over 1 billion dollars in damages.
How Does Hail Form?
Hail forms as a result of the strong updrafts common in severe weather systems. When a strong convective cell
forms, warm air rises and cool air sinks. If there is a sufficient amount of supercooled water
, accumulation of ice can begin in the clouds.
Rising air will often reach a point in the atmosphere that is below freezing (hence, ice will form). The ice is suspended in the air by the strong updrafts and will later fall back down. This process will occur over and over adding layer upon layer to the hailstone. If you cut a hailstone in half, you would see alternating concentric layers inside it. As the hail falls, it may melt to varying degrees only to be picked up again and carried high into the atmosphere to re-freeze. Therefore, very large hailstones form with many repeated cycles.
What is the Largest Hailstone Found
Many states have records for the largest hailstones. Nationally, the largest hailstone
on record based on diameter and circumference was found in Aurora, Nebraska on June 22, 2003.
What are the Dangers of Hail?
The formation of hail means there is usually a severe thunderstorm. A severe thunderstorm is the precursor of tornadoes
and should be closely monitored.
Also Known As: hailstones