Tornadoes are visually one of the most famous products of severe weather but hail deserves more attention.
The life cycle of hail truly shows the complexities and the impressive structure of a storm. Hail begins as simple rain droplets that are thrown into the upper atmosphere with rising air. We call this rising air an updraft. The stronger the updraft the large the hail that storm can produce.
Those rain droplets freeze in the colder upper level air and become tiny hail. It’s tiny in size at first but due to a more complex physical process moisture defuses onto its surface and the hail slowly grows. The most rapid growth occurs when the hail falls back down into middle of the clouds and collides with supercooled water droplets.
These supercooled water droplets freeze on the surface of the hail and the overall hailstone begins to grow rapidly. The more times it’s tossed through the cloud the larger and larger it gets.
Once hail gets to the size of a quarter it is considered severe because of its damage potential. Hail in East Texas can easily get to the size of a softball, only a few weeks ago in Jacksonville we saw a near softball size hail event!
If you get caught in hail seek shelter immediately, large hail can cause serious injury.
Strong updrafts are a sign of a powerful storm but what happens when a storm gets too strong?
Upper level air of the storm is much cooler and contains cold water and hail. As this falls to the surface it can often cut off the updraft. The updraft is the only thing keeping all that rain and hail up in the air!
Once the updraft is cut off then the flood gates are open and it’s possible for the whole clouds to collapse to the ground. This is called a microburst. Microbursts can be as wide as two and a half miles, if it’s any larger we classify this as a macroburst.
Microbursts and macrobursts are especially dangerous to airplanes that rely on consistent air direction to produce lift. Fall air can result in planes drastically losing altitude. All major airports are required to have microbursts sensors on their runways.