Why do tornadoes have the shape of an inverted cone?
• Exactly how tornadoes form is not completely understood, but we know that they usually occur during thunderstorms and when volumes of air are unstable. They are the result of updrafts that are created when warm, moist air meets cold, dry air. First, a horizontally spinning column of air called a vortex can form when there are different wind speeds at different altitudes. If this vortex collides with a violent updraft, it can be knocked into an upright position; when the vertically spinning vortex reaches the ground, a tornado is born.
To understand why tornadoes are often shaped like inverted cones, you need to remember that air pressure decreases at higher altitudes. Near ground level, the air surrounding the vortex is at high pressure and crushes the spinning column of air. As the altitude increases, the pressure outside the tornado ...
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