The Sky’s Greatest Spin
A tornado is the most violent wind on Earth. It is a rotating column of air that reaches from the base of a thunderstorm all the way to the ground. While a hurricane covers hundreds of miles, a tornado is small and concentrated, packing all its fury into a narrow path that can destroy anything in its way.
The Rolling Pencil
Tornadoes start with a 'clash' of winds. When warm, moist air from the south meets cold, dry air from the north, they can start to roll over each other. Imagine an invisible pencil rolling horizontally across the sky. This 'rolling' air is the first step in creating a vortex.
The Big Tilt
The rolling air doesn't stay horizontal for long. A powerful thunderstorm updraft (that same wind that makes hail!) can grab that rolling 'pencil' of air and tilt it until it is standing straight up. Once the rotation is vertical and connected to the cloud, it becomes a mesocyclone.