# How Tornadoes Form

Watch a supercell storm build a tornado from warm air, wind shear and a spinning updraft, and tune the ingredients yourself

By cosmic\-fox\-0f21ea73

Topic: Earth & Geography

[Open the interactive Jig](https://ask.jig.com/j/3ipoxgacRC8n)

## Transcript

### 1. How Tornadoes Form

A spinning column of air reaches down from a great thunderstorm and touches the ground\. That is a tornado\. Watch the wind itself: every glowing streak is a little parcel of air riding the storm\.

Drag to turn the table and look all around the storm\.

### 2. Warm, wet air below

It starts on a muggy spring day\. The sun warms the lake, and its water rises as invisible vapour\. Warm, moist air \(orange\) flows low from the lake toward the storm, under cooler, drier air \(blue\)\. It rises, its water turns into cloud, and rain falls back toward the lake\.

Vapour means water in the air as a gas\. More moisture means the cloud forms lower and the storm has more fuel\.

### 3. Winds that change with height

Up high, the wind blows faster than near the ground\. This change is called wind shear\. It sets the air between them rolling, like a pencil rolled between your hands, making an invisible tube of spinning air lying on its side\.

### 4. The updraft stands it up

A strong rising current inside the storm, the updraft, pushes up the middle of the rolling tube\. The spin tips from lying down to standing up\. Now the storm's rising air is turning too\.

### 5. A spinning storm

A thunderstorm with a turning updraft is called a supercell, and its spinning heart is a mesocyclone\. It can be 1\.6 to 10 kilometres wide, much wider than any tornado\. Under it, part of the cloud base sinks into a lowered, slowly turning wall cloud\.

Most supercells never make a tornado\. Something more has to happen\.

### 6. Stretch it, spin it faster

A stronger updraft stretches the spinning air tall and thin\. Like a skater pulling in their arms, the narrower the spin, the faster it turns\. Slide the updraft up and watch the column tighten and speed up\.

### 7. Touchdown

Rain\-cooled air sinks on the back of the storm in a rear\-flank downdraft and wraps around the spin\. It helps pull the rotation down to the ground\. When the spinning winds reach the ground, a whirl of dust rises, even before the cloud funnel touches down\.

Most tornadoes have winds under 180 km/h \(110 mph\)\. The rare strongest top 480 km/h \(300 mph\)\.

### 8. Rope out

In the end, cool downdraft air cuts off the warm air feeding the updraft\. The tornado thins into a twisting rope and fades, often within a few minutes\. Press the button to see the end, then step back and try new mixes of moisture, shear, updraft and downdraft\.

When a tornado warning is issued, go to a basement or a small inner room\.