How does freezing rain form?

Freezing rain usually starts its life as snow, sleet or hail. It then falls through a warmer part of the atmosphere and melts.

Following this, it falls through cold conditions and "supercools", becoming almost as cold as ice and is just above freezing. As this supercooled water hits the ground, it spreads out and freezes on contact, forming a perfectly smooth, transparent layer of ice.

This creates a slippery glaze over most surfaces, which makes driving or walking almost impossible.

A Met Office spokesperson explained: "Freezing rain forms when rain is falling from a warm parcel of air, but when it goes through very cold air and becomes super-cooled.

"It doesn't become ice but gets very close to that. When it gets to a surface, it freezes on contact, especially if the surface is cold. As soon as it hits the surface it becomes ice. That's why it can become dangerous as you just think it's rain and you go out on the road and the whole road is ice.