It's important to understand that a tornado is formed by the updraft of a storm cell, meaning that air is being pulled up from ground level into the supercell on the back side of the storm. When this updraft begins to rotate, it starts to lower towards the ground, initially forming a wall cloud. If it continues to grow, it will develop a funnel and then a tornado.

Quite often you will see a funnel that does not look like it is in contact with the ground, but a debris cloud directly underneath the funnel shows that it really is. You will see this exact phenomenon in the tornado videos I posted from Central Illinois two weeks ago.

So from the aspect of the fact that a tornado (and a hurricane, technically) is formed from rotating air that is moving from the surface up into the storm, you could say that tornadoes form from the ground up. Sort of.

However, the conditions necessary for a storm to spawn a tornado have to be just right at multiple altitudes, not just at ground level. Therefore, in my opinion, it is too simplistic an explanation to say that tornadoes form from the ground up. It's more complicated than that.

And that's just talking about the classic tornadic supercell. Tornadoes that form from squall line storms require completely different dynamics. A majority of Indiana's tornadoes occur from squall line storm systems instead of supercells, so we took an advanced spotting class from the weather service dealing with just that kind of storm.