Tornado.

Tornado.

Pressure trace showing the passage of a tornado.

Weather observations showing the passage of a tornado at a station in Oklahoma (24 May 2011).

Visible and infrared satellite image of a tornadic thunderstorm.

Supercell schematic.

Radar hook echo.

Tornado alley.

Tornadoes are most likely in late afternoon.

Tornadoes are most likely in Spring.

YouTube tornado video

YouTube tornado video (best: 4:10-5:10)