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
- Orkney aera
- Western Isles
- Ross and Cromarty
What weather warnings are in place?
The Met Office has issued a yellow weather warning for wind across the majority of the UK.
The notice says: “Strong southwesterly winds are expected to develop across much of England, Wales and southern Scotland during Friday.
“Wind gusts of 45-50 mph are expected fairly widely inland with gusts of 55-60 mph possible around coasts and over hills. Winds are then expected to gradually ease during late afternoon and evening.”
The warning states: “Strong winds on Friday are expected to lead to some travel disruption and perhaps some temporary power disruption.”
The Met Office says to expect:
- Some delays to road, rail, air and ferry transport
- Some bus and train services likely affected, with some journeys taking longer
- Delays for high sided vehicles on exposed routes
- Some short term loss of power and other services
- Coastal communities, routes and sea fronts likely affected by spray and/or large waves
- Some damage to trees with debris on roads
How do I stay safe in a storm?
Gales are reportedly the most common cause of damage and disruption in the UK, with the average cost of damage each year at least £300 million according to the Met Office.
There are steps that you can take to ensure your safety during a storm.
Before the storm you should secure loose objects such as ladders, garden furniture or anything that could be blown into the likes of windows and other glazing.
You should also close and securely fasten any doors and windows.
Park vehicles in a garage, as this is where they will be safe from damage, or if you don’t have a garage, keep your vehicle clear of buildings, walls and fences.
During a storm, try to stay indoors as much as possible.
After a storm, be careful not to touch any electrical or telephone cables that have blown down, and do not walk too close to walls, buildings or trees as they could have been weakened during the storm.
You should also make sure to check on any vulnerable neighbours or relatives to make sure that they’re safe and their belongings haven’t been damaged.