1. what is it/ how does it form
2.historical example
3. how humans have prepared

A tornado to form you need warm moist air from the gulf of mexico and cool dry air from Canada increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere Rising air within the updraft tilts the rotating air from horizontal to vertical.

Oldest Known Tornado Photo - Date: 1884 August 28 Historic NWS Collection 22 miles southwest of Howard, South Dakota Courtesy NOAA/Department of Commerce

People have to make their houses stronger or have floors underground to prevent from them getting hurt.