Tornadoes

Learn how rapidly rotating storms can connect cloud and ground.

About Tornadoes

A tornado is a violently rotating column of air extending from a thunderstorm to the ground. Tornadoes occur in many countries, though the United States experiences especially large numbers because of its geography and storm climate.

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Thunderstorm — ThunderstormThunderstorms form when warm moist air rises into an unstable atmosphere.

Tornado — TornadoTornadoes are rapidly rotating columns of air connected to thunderstorms.

Hurricane — HurricaneTropical cyclones are organized rotating storm systems fueled by warm ocean water.

Snowstorm — SnowstormWinter storms can combine snow, wind, cold, and low visibility.

Rotation

Many strong tornadoes develop from rotating supercell thunderstorms.

Funnels

A funnel cloud is a visible condensation funnel extending from a cloud.

EF Scale

The Enhanced Fujita Scale estimates tornado intensity from damage.

Radar

Doppler radar can detect rotation inside thunderstorms.

Warnings

A tornado watch means conditions are favorable, while a warning means a tornado is occurring or imminent in the warned area.

Outbreaks

Some weather systems produce many tornadoes over a region.

Debris

Flying debris is a major tornado danger.

Safety

Know the safest shelter before storms arrive.

Rotation

Wind shear can create horizontal rotation that a storm updraft tilts and stretches.

Funnels

A tornado may already be on the ground even if condensation does not reach all the way down.

EF Scale

Ratings range from EF0 to EF5 and are based on expected wind effects on specific structures.

Radar

Radar does not see every tornado directly, but velocity patterns help forecasters identify dangerous circulations.

Warnings

People should follow official local alerts.

Outbreaks

Large outbreaks can span several states and last many hours.

Debris

Interior rooms on the lowest level of a sturdy building provide better protection than windows or vehicles.

Safety

Basements, storm shelters, or small interior rooms away from windows are preferred when available.