What is freezing rain? What you need to know
Freezing rain is more common in the US, and is hardly ever seen in the UK, but we are about to get some.
Thursday 1 March 2018 13:59, UK
As the UK endures days of severe cold weather, a significant build up of ice due to freezing rain could make conditions even worse.
Freezing rain is expected to fall over some areas of southern Britain from late on Thursday evening to the early hours of Friday.
Here's what you need to know.
What is freezing rain?
It is rain that has become "supercooled" as it falls from the AG百家乐在线官网.
It starts as snow, ice or hail high up in the atmosphere, but as it travels down it melts through a layer of warmer air, then refreezes again through a layer of colder air near the surface.
Why is it so dangerous?
As soon as it hits the ground it turns to ice.
The ice is very clear, often referred to as black ice, because it is so difficult to see, making it treacherous for pedestrians and drivers.
Although we hear about black ice a lot, it's not usually as a result of freezing rain.
What usually happens is the rain falls onto already frozen surfaces, or wet surfaces which then freeze as temperatures drop below 0°C overnight.
Can is cause a lot of damage?
It has the potential to.
Freezing rain, when it falls onto surfaces, can be very dangerous.
If it hits power lines or tree branches, depending on how much rain there has been, the weight of the ice can cause them to break off because they can't support the weight.
It can also make it pretty difficult to open your car door if there is enough of it.
Have we ever had freezing rain in the UK?
It is a very rare occurrence in the UK.
The conditions needed for freezing rain to occur are very specific, and it usually happens when the air is extremely cold, like it is now.
What precautions should people take?
The best thing people can do is take extra care when travelling. As it is so hard to see, it's difficult to judge just how icy road surfaces are.
The RAC's road safety spokesman, Pete Williams, says freezing rain is "arguably the most treacherous of all conditions for motorists".
They urge people not to drive unless necessary, but say those who do need to should check they have plenty of fuel and oil and check their tyre treads.
They also encourage drivers to make sure their lights are working and check they have screenwash.