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What exactly is a weather bomb and why does Storm Doris count as one?

What exactly is a weather bomb and why does Storm Doris count as one?
What exactly is a weather bomb and why does Storm Doris count as one? What exactly is a weather bomb and why does Storm Doris count as one?

Winds of up to 90mph have been battering Britain, all because of Storm Doris.

But the Met Office has made the whole thing sound a lot scarier by announcing that Doris is actually a “weather bomb”.

Here’s everything you need to know about the meteorological phenomenon we’re currently living through.

What is a weather bomb?

Technically, it’s just an area of low pressure, but one that’s formed dramatically in a short period of time.

For a storm to qualify, it needs to drop 24 millibars (a pressure unit used by meteorologists) in 24 hours.

Because of a powerful jet stream high in the atmosphere coming from the west, Storm Doris actually dropped 30 millibars in a day, easily qualifying as a weather bomb.

What’s pressure got to do with it?

Alex Deakin from the Met Office explains (Met Office)

The lines on the above map, called isobars, connect areas experiencing equal atmospheric pressure.

The closer together they are, the stronger the winds. In the picture, they are quite close together across England, hence the wind, which anyone who’s been outside today can vouch for.

What causes it?

A satellite image of the weather bomb (NEODAAS/University of Dundee)

An even scarier-sounding name used by meteorologists to describe what we’ve seen with Storm Doris is an “explosive cyclogenesis”.

It happens when dry air in the stratosphere, the second-closest atmospheric layer to the Earth’s surface, flows to an area of low pressure (which we’ve definitely seen with Doris).

This makes the air in the low pressure area rise and spin, causing a cycle of lowering pressure.

What does this all mean?

Flights have been cancelled but those landing look terrifying (Danny Lawson/PA)

Well, there’s still a weather warning for wind across the UK, and in some parts it’s an amber warning, which means you should “be prepared”.

You don’t need to start stockpiling tins just yet, but expect some serious travel delays, potentially a few flying objects and fallen trees.

There’s a severe warning for ice on Friday, but by Saturday the weather bomb should be long gone.