Tornado

What causes a tornado to spin so fast, and not always rotate in the same direction?
The stock answer has been the effect Aways Coriolis, but I've also read that Coriolis is only effective in leading hundreds of miles through weather patterns and the small diameter of a tornado would be no such effect of the small Coriolis force would not cause the violent rotation. It is the rotation track up / down of Ecuador to the Convention on the large circular motion?
Most tornadoes are raised by a portion known as a storm mesocyclone. It's a fairly wide area of rotation (usually 5 to 10 miles across) at lower levels Halfway through the storm. For reasons not understood, an area in the mesocyclone narrows and as the skater pulling in her arms, as the diameter of rotation decreases, increases speed. From there, the tornado is based on development to the surface. The Coriolis effect, although nonzero in the case of tornadoes, is extremely low and not really about the direction of rotation. Most tornadoes rotate counterclockwise, but I run a little (counterclockwise cyclone).
Tornado Destruction