A tornado is born from a powerful storm called a supercell. Tornadoes have been reported in all states, but most tornadoes happen in the central parts of America called “Tornado Alley.” In some supercells, warm, moist air rises quickly into the atmosphere. Winds blowing at different speeds at different parts of the supercell produce wind shear and cause a horizontal, rotating column of air. A funnel cloud will form as the air column rotates faster and more tightly within the supercell. The rain and hail within the storm cause the funnel cloud to touch the ground resulting in a tornado. The strength of a tornado is measured by what’s called the Fujita scale. The weakest tornadoes feature winds of 40-78 miles per hour, while the strongest tornadoes have winds of up to 318 miles per hour. All tornadoes can be devastating, especially if they touch down in areas with lots of people.