Tornadoes
qTornadoes are violently rotating columns of air that extend from a thunderstorm cloud to the ground. 
qOn average, over 1,000 tornadoes are reported in the US each year.
qTornadoes primarily develop within supercell thunderstorms, but also form in thunderstorms along squall lines, near the ends of thunderstorm bow echoes, and within landfall hurricane.
qMost tornados are short lived.