The Met Office has issued yellow weather warnings for wind - here's everything you need to know

Storm Ellen brought very strong winds to parts of the UK earlier this week, with yellow warnings for wind continuing on Friday (21 August).

But what is wind and what exactly causes it? This is everything you need to know about wind - and what to do if you’re caught in a storm.

Where does wind come from?

The Met Office describes wind as “air in motion, travelling between areas of different pressure”.

To understand where wind comes from, first, you need to understand what atmospheric pressure is.

“Pressure at the earth’s surface is a measure of the ‘weight’ of air pressing down on it. The greater the mass of air above us, the higher the pressure we feel, and vice-versa,” the Met Office explains.

The importance of this is that air at the surface will want to equalise the difference by moving from high to low pressure areas, which is what we know as wind.

Wind is caused by differences in atmospheric pressure, and we get these differences by the rising and sinking of air in the atmosphere.

If it weren’t for the rising and sinking motion in the atmosphere, then not only would we have no wind, but we’d also have no weather.

What are the windiest areas of the UK?

The windiest places in the UK have been recorded at the top of mountains, usually in the west of the country, according to the Met Office.

Wind is measured in a unit of speed called knots.

The strongest ever gust of wind in the UK was recorded at the Cairngorm Summit on 20 March 1986 with 150.3 knots, which translates to 173 miles per hour.

These are the top 10 windiest places in the UK, based on the 1981-2010 annual average wind speed (in knots):

• Shetland area
• Buteshire
• Orkney aera