How Do Tornadoes Form?
Tornadoes are associated with large (supercell) thunderstorms that often
grow to over 40,000 feet. A column of warm humid air will begin to rise
Air Rotates Because of Wind Shear.
How the column of air begins to rotate is not completely understood by
scientists, but one way the rotation appears to happen is when winds at
two different altitudes blow at two different speeds creating wind shear.
For example, a wind at 1000 feet above the surface might blow at 5mph
and a wind at 5000 feet might blow at 25mph. This causes a horizontal
rotating column of air.
Faster Spin Makes a Funnel Cloud.
If this column gets caught in a supercell updraft, the updraft tightens
the spin and it speeds up (much like a skater's spins faster when arms
are pulled close to the body. A funnel cloud is created.
The Funnel Rotates and Touches Down.
The rain and hail in the thunderstorm cause the funnel to touch down creating