Tornado, decoded. The sky, spinning.
A tornado is a violently rotating column of air that reaches from a thunderstorm down to the ground. Most are small and short-lived; a few are among the most destructive forces on Earth. This page is the short version of how one forms, how forecasters rate it, and the one shelter rule that matters when a warning sounds.
WHAT IT ACTUALLY IS
A thunderstorm, spinning.
A tornado starts inside a severe thunderstorm, where rising warm air meets wind that changes speed and direction with height. That wind shear gets the air turning, the storm's updraft stretches the spin upright, and the rotation tightens into a funnel that touches the ground. The visible funnel is only the middle of it — the damage comes from the winds around it, which can throw debris faster than a highway car, and from the pressure drop at the center, which is why windows are the last place you want to stand near.
THE EF SCALE
Rated by damage, not by wind measured directly.
Forecasters rate tornadoes on the Enhanced Fujita scale, EF0 to EF5, and the rating comes from the damage left behind, not from an anemometer inside the storm — nobody measures those winds directly. EF0 means light damage, like branches down and shingles peeled; EF2 means roofs torn off and large trees snapped; EF5 means well-built houses swept clean off their foundations. The scale tells you what a tornado did, which is how the next one's warnings get sharper: most tornadoes are EF0 or EF1, and the violent EF4 and EF5 storms are rare, which is exactly why they get the loudest warnings.
WHAT TO DO ABOUT IT
Warning means now, and the lowest floor wins.
A tornado watch means conditions are favorable and one could form — check your plan and keep an eye on the sky. A tornado warning means one has been spotted or indicated by radar where you are — go now to the lowest floor, an interior room away from windows, and protect your head. Never shelter under an overpass, where the wind funnels faster, and never stay in a mobile home or a car — get to a sturdy building or a designated shelter. Brzzy's forecast, live radar, and severe weather alerts turn the same kind of ground truth into a plain-language answer before the sky turns: go outside, or get inside now.
What is a tornado?
A tornado is a violently rotating column of air that extends from a thunderstorm to the ground. It forms when wind shear gets air turning inside a severe thunderstorm and the storm's updraft stretches that spin upright into a funnel.
What is the EF scale?
The Enhanced Fujita scale rates tornadoes EF0 to EF5 based on the damage they leave behind, since their winds are almost never measured directly. EF0 means light damage like branches down; EF5 means well-built houses swept clean off their foundations. Most tornadoes are EF0 or EF1.
What is the difference between a tornado watch and a tornado warning?
A watch means conditions are favorable for a tornado to form — check your plan and keep watching the sky. A warning means a tornado has been spotted or indicated by radar where you are — go now to the lowest floor, an interior room away from windows.
Where is the safest place during a tornado?
The lowest floor of a sturdy building, in an interior room away from windows, protecting your head. Never shelter under an overpass, where wind funnels faster, and never stay in a mobile home or a car — get to a sturdy building or a designated shelter.
Does Brzzy warn me about tornadoes?
Brzzy shows your local forecast with hourly updates, live radar, severe weather alerts, GIF forecasts, and activity ratings that weigh the sky for your plans. Brzzy is free to download on iPhone.
More from Brzzy: Full weather glossary, Thunderstorms, Storm.
