What is black ice? Warning to drivers as 'big refreeze' hits UK roads

Drivers have been warned of hazardous road conditions following "a big refreeze overnight" after recent snowy weather.

Motorists in some rural have been urged to consider staying at home to avoid lethal black ice.

The Met Office has extended a yellow warning for snow and ice covering northern Scotland and north east England until noon on Friday.

RAC spokesman Simon Williams said some roads would be “treacherous” after "a big refreeze overnight”.

Jack Cousens, head of roads policy for the AA, warned motorists were “slipping and sliding” as sub-zero temperatures had frozen snow.

Vehicle breakdowns reached record levels on Monday due to freezing conditions across the UK.

The RAC said it received around 12,000 call-outs from stranded motorists, the most for a single day since the company began uniformed patrols in 1901.

Simon Williams, spokesman for RAC Breakdown, told the Independent that drivers in rural areas should “delay or even abandon their plans”.

Watch: Snow, black ice and fog cause travel chaos across UK

What is black ice?

The frozen glaze which forms on roads and walkways is called ‘black ice’ because it’s transparent and allows the surface below to be seen, the Met Office says.

How do you spot black ice?

Black ice is dangerous as it can appear almost invisible to drivers.

The RAC says black ice can sometimes appear as a glossy sheen on the road.

It adds “you may see it glinting in the sunlight, or spot cars ahead swerving for no obvious reason.”

Read more: London weather: Travel chaos as capital blanketed by snow and freezing fog

What do you do if you drive on black ice?

Hazards like black ice can prove lethal if you don’t adjust your speed and driving style while driving over it, the AA warns.

It advises motorists always to leave plenty of space behind other vehicles because stopping distances can be ten times longer on icy roads.

Drivers are also advised to use main roads as much as possible and to drive "slow and steady".

Read more: UK Weather: OK, But When Will This Period Of Extreme Cold Be Over?

Motorists should allow extra time as there may be delays on their normal routes and they should pack winter essentials, including warm, waterproof layers, a shovel, a torch, fully charged mobile phone and a flask of hot drink - just in case they break down.

AA president Edmund King warned black ice can be a bigger danger than snow because it is not as visible.

He said: “Often, when you've had snow, it melts a bit, then it freezes overnight.

"Then the next morning you cannot see the ice. It's black ice or you just can't see it.

“It is really the kind of silent killer.”