Apr 12, 2016 1:22 PM
Joe Knows: Giant hail falls in Texas with some stones as big as baseballs
Golf ball-sized hail fell in Texas Monday, damaging cars and roofs across the state.
A hail producing thunderstorm needs to have a strong updraft of rising warm air into the storm. Extremely large hail requires an EXTREME updraft!
The warm air rises up and cools once it's into the freezing level, high up in a thunderstorm's cloud. Hail forms as these super-cooled droplets and ice crystals freeze onto each other. The strong updrafts can suspend these hail stones in the air for a time where they can continue to refreeze and grow. Eventually, gravity will apply a force on the hail to bring it to the earth's surface, most of the time in pea-sized or quarter-sized hail. If the updraft is much stronger than the influence from gravity, the hail stone will continue to grow even more.
Updrafts with the speed of 80 to 100 mph can race up into the core of a thunderstorm. These wind speeds prevent the hail from falling and can turn hailstones into the size of baseballs, softballs and even basketballs in the most extreme case. Eventually, hail reaches a size that the updraft can no longer keep aloft and the hail stones will fall to the earth's surface. Extremely large hailstones can be costly in terms of damage and can be deadly if they strike an animal or human's head.