Hail is a form of precipitation in a form of balls or irregular lumps of ice (hailstones), 5 mm – 50 mm in diameter on average, although much larger is reported from severe thunderstorms. It is always produced by thunderclouds and is composed of transparent ice or alternating layers of transparent and translucent ice at least 1 mm thick. Hail forms on condensation nuclei such as dust, insects, or ice crystals, when super cooled water freezes on contact. Once a hailstone becomes too heavy to be supported by the storm's updraft it falls out of the cloud and many times ends up denting vehicles. This is where Hi Tech PDR can save the day! Hi Tech PDR has a team of traveling hail chasers that will repair damage in all areas of the United States. If your area is hit by a major hail storm, call Hi Tech PDR to have their highly trained hail chasers repair your lot.

Ideal conditions for hail formation

Hail forms in strong thunderstorm clouds, particularly those with intense updrafts, high liquid water content, great vertical extent, large water droplets, and where a good portion of the cloud layer is below freezing (< 32 °F (0 °C)). For this reason, hail is most common in mid-latitudes during early summer where surface temperatures are warm enough to promote the instability associated with strong thunderstorms, but the upper atmosphere is still cool enough to support ice. Accordingly, hail is actually less common in the tropics despite a much higher frequency of thunderstorms than in the mid-latitudes because the atmosphere over the tropics tends to be warmer over a much greater depth. Also, entrainment of dry air into strong thunderstorms over continents can increase the frequency of hail by promoting evaporational cooling which lowers the freezing level of thunderstorm clouds giving hail a larger volume to grow in.

Hail is also much more common along mountain ranges because mountains force horizontal winds upwards, thereby intensifying the updrafts within thunderstorms and making hail more likely. Certain locations in North America (such as the area around Calgary, Alberta) have gained the nickname "Hailstorm Alley" among meteorologists for the frequency of hailstorms and their severity.