Stay up to date with notifications from The Independent

Notifications can be managed in browser preferences.

How Tornadoes Can Happen - Even In Genteel Sussex

Friday 09 January 1998 01:02 GMT
Comments

Your support helps us to tell the story

From reproductive rights to climate change to Big Tech, The Independent is on the ground when the story is developing. Whether it's investigating the financials of Elon Musk's pro-Trump PAC or producing our latest documentary, 'The A Word', which shines a light on the American women fighting for reproductive rights, we know how important it is to parse out the facts from the messaging.

At such a critical moment in US history, we need reporters on the ground. Your donation allows us to keep sending journalists to speak to both sides of the story.

The Independent is trusted by Americans across the entire political spectrum. And unlike many other quality news outlets, we choose not to lock Americans out of our reporting and analysis with paywalls. We believe quality journalism should be available to everyone, paid for by those who can afford it.

Your support makes all the difference.

If you thought tornadoes were just an American experience, as in the film Twister, think again. About 50 hit Britain each year, but most don't hit populated areas, and are smaller than yesterday's storm.

Tornadoes have their origins in thunderstorms. In the United States, meteorologists have learnt to watch for rain patterns with an "S" or "6" shape - indicative of a funnel cloud about to form, or already rotating. This usually happens along a storm front when large masses of cold dry air, fast-moving frigid dry air, and low-lying warm wet air collide.

The masses begin rotating, with the warm air trapped beneath, trying to rise, and the cold air trying to fall. If the twisting warm air punches a hole up through the cold air, the scene is set for a funnel cloud.

Generally, half of funnel clouds dissipate, but the others worsen, as the winds speed the funnel up. It tightens and extends down towards the ground. When it touches, the tornado is born.

Some have wind speeds of more than 250mph, and move across the ground at more than 50 mph. Their severity is measured against the 7-point Fujita scale, ranging from F0 to F6, the "inconceivable tornado" with winds of more than 370mph, which isn't expected to happen on Earth. Even F2s and F3s are killer tornados.Andy Yeatman, spokesman for the Meteorological Office, said: "[The Selsey] tornado was considerably more destructive than those we normally witness."

The funnel core is the most vicious killer for anyone unlucky enough to be sucked into it: people are sandblasted to death by tiny debris.

Join our commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in