A tornado is a rapidly rotating column of air in contact with both a cumulonimbus cloud and the ground. The simulation models the converging updraft: surface inflow spirals inward (conservation of angular momentum), accelerates upward through the funnel, and is carried away aloft. Pressure drops to 100 mbar below ambient near the core.
Click anywhere to seed the initial vortex. Use the wind speed slider to control inflow intensity and the rotation slider for angular momentum. The humidity control affects condensation funnel visibility. Watch particles trace helical paths — inner ones spiral tightly, outer ones describe broad arcs.
The most destructive tornadoes (EF5) have wind speeds exceeding 320 km/h. The Fujita scale, developed in 1971, rates damage from EF0 (minor) to EF5 (incredible). The United States averages ~1,200 tornadoes per year — more than any other country — concentrated in "Tornado Alley" where dry polar air meets warm Gulf moisture.