What is thundersnow? Met Office weather warning for parts of Britain

Heavy snow and lightning strikes forecast, with possibility of power cuts

Households across parts of Britain have been put on alert for possible power cuts, as “thundersnow” and lightning strikes are forecast before the weekend.

The UK's Met Office issued two weather warnings for snow, ice and thunderstorms through to Friday, predicting travel disruption.

What weather warnings are in place?

One warning, which stretches from 8pm on Thursday to 11am on Friday, covers parts of northern England and the Midlands, western and central Scotland and several areas in Northern Ireland.

Meteorologists have said “frequent sleet, hail and snow showers” are likely.

They said “brief power outages” are possible and there is a risk of lightning strikes.

Travel disruption is also predicted, with roads, railways and cycle paths set to face challenges.

Wintry conditions in Braemar, Aberdeenshire, Scotland. Photo: PA

What is thundersnow?

Forecasters said several areas could experience thundersnow, which forms when winter thunderstorms release heavy downpours of snow while lightning strikes are happening. It is a rare phenomenon which occurs no more than a handful of times each year.

“We have got an area of high pressure across the UK that will remain in situ until the early hours of tomorrow morning. Then we will start to see the weather front coming in,” Grahame Madge, spokesman for the Met Office, said.

“As conditions get cold tonight, we’re seeing temperatures drop down to freezing quite widely.

“As we get the cold air, that will bring the temperatures right down, we’ve got the weather front coming in from the west and that moisture is going to bump into the cold air and where you get that you will get snow.”

He said that the prospect of thundersnow was driven by the same conditions that cause thunder in the summer, the difference in temperature between the ground and the surrounding air.

A snow plough drives along the snow-lined Buttertubs Pass, near Hawes in the Yorkshire Dales, northern England. PA

“Because you have got that differential it’s possible, quite easily, for warm air at ground level when it heats up to start to rise very quickly up through the cold air and that’s what creates the potential for thunderstorms, so we are likely to see along with the other wintry showers, likely to see hail and snow,” he said.

The warning comes just weeks after the UK and Ireland were battered by Storm Barra, which brought heavy snowfall, gusts of wind up to 128 kilometres an hour and power cuts.

A separate warning was in place until Thursday afternoon extending from the Highlands of Scotland, through Glasgow and Edinburgh and into the north of England, for up to two hours of snow.

As much as 10 centimetres of snow was forecast on the highest ground, with icy patches creating dangerous conditions for pedestrians.

Following a record-breaking mild New Year, Scotland is on track to record chilly temperatures before the weekend.

Where has thundersnow hit so far?

Thundersnow batted parts of Scotland overnight on Friday, with South Lanarkshire has been particularly badly hit.

Traffic Scotland warned motorists to exercise extra caution and shared photos of the M8 and M80 motorways covered in snow.

“Heavy snowfall overnight affecting many routes this morning,” Traffic Scotland said.

“Both surface water and flurries of snow affecting the M8 for those travelling east today. Surface water also affecting the M9 and M90.”

A 48kph restriction has been imposed on the M8.

Drivers in East Dunbartonshire were forced to abandon their vehicles due to heavy snow blocking roads.

Police urged drivers to “stay at home if you can, and travel later once the roads are a bit clearer”.

“There are a number of vehicles abandoned throughout East Dunbartonshire due to the weather,” they added.

Several councils and schools have told staff and pupils not to come in until 10am in the hope that the snow and ice will have at least partially melted by mid-morning.

Three schools in the Scottish Highlands have been closed due to the extreme weather.

ScotRail said passengers should take care because station platforms and paths may be slippery due to ice and slush.

Updated: January 7th 2022, 10:13 AM