Friday, May 10, 2019

What Is Hail?



Details on Hailstorms
A hailstorm is one of the most damaging types of weather events. Hail can puncture roofs, fell crops and smash car windshields. The US holds the unfortunate record of the largest officially measured pieces of hail:
  • 18.74 inches (47.6 cm) circumference  in Aurora, Nebraska on June 22 2003;
  • 18.62 inches (47.3 cm) in diameter in Vivian, South Dakota, on July 23 2010.

So, What Exactly Is Hail?
Hail forms in large and tightly loaded thunderstorm clouds when a sizeable part of the cloud has a temperature below freezing – 0 degrees Celsius (32 degrees Fahrenheit). However, as you can see from the dates of the record sized hail pieces, this phenomenon does not occur during winter.

Hail occurs most frequently during spring and summer and tends to affect areas prone to tornadoes and high winds. Other factors that favor hail are:
  • Area: continental interior;
  • Position on the globe: mid-latitudes;
  • Dry air masses moving into strong thunderstorm formations.

Thus, coastal areas and the tropics, although subject to more rainfall, are less likely to be hit by hail.

Can We Anticipate an Upcoming Hail?
The answer is yeas. Weather radars can detect tightly packed thunderstorm clouds. However, specialists also need to know the atmospheric conditions in order to predict whether all the conditions that favor hail formation are met (low temperature at high altitudes, sudden dry air movement into the clouds).