Tornado Damage

When I was initially researching the natural phenomena of a tornado I was unsure of how to mathematically describe the potential for destruction that a tornado possess. Then I became mindful of the linear momentum equation which states that the summation of the forces is equal to the summation of the mass flow rates multiplied by the velocities. When you think about air and its very small density it seems relatively harmless. Even with a relatively small mass flowrate, at the high wind velocities (between 40 and 320 mi/hr.) a tornado possess the resulting forces can be tremendous.