Chance of '˜thundersnow' as severe weather warnings issued for Northern Ireland

The Met Office has issued yellow weather warnings for wind and snow across Northern Ireland.

Wednesday, 11th January 2017, 3:40 pm
Updated Wednesday, 11th January 2017, 4:42 pm

The Met Office said gusts of up to 60mph and snow were expected.

Major tourist attractions have been closed because of bad weather.

Castle Ward and Rowallane in Co Down and Springhill in Co Londonderry have both been shut by the National Trust.

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Carrick-a-Rede rope bridge outside Ballycastle, County Antrim, has also been closed.

Meanwhile all ferry sailings between Ballycastle and Rathlin Island have been cancelled due to high winds.

A Translink this afternoon revealed they have a number of contingency measures in place ahead of the wintry weather forecast.

They issued a video showing the efforts our crews go to in order to keep our services operational. See it here.

Communications Manager Lynda Shannon said: “We have stockpiles of salt to tackle ice and snow on our platforms and bus waiting areas; and we have crews on standby to remove debris from railway lines.

“We also liaise with Transport NI in the event of road closures or diversions”.

Passengers can keep up to date with the latest travel news on the Translink website and app, via Twitter @Translink_NI or through our contact centre 028 90 66 66 30.

A Met Office forecaster told Johnston Press: "There will be coastal gales as well as a risk of hail and thunder in some locations.”

Forecasters have not ruled out the possibility of “thundersnow”, where rain associated with a thunderstorm falls as snow.

What is thundersnow?

Basically, it’s exactly as the name suggests - a thunderstorm with rain replaced by snow.

“All that really needs is for thunder to happen at the same time as the snow,” according to Met Office meteorologist Emma Sharples.

“Where you get very active or vigorous shows, which is what we are going to see, then we could well get some thunder as well. It is definitely possible.”

What’s the science behind it?

Again, thundersnow is similar to a thunderstorm, with warm air rising from the ground meeting cool air sinking from above.The warm air condenses to form droplets of moisture, and as the droplets cool, they form a cloud. The expanding cloud may then meet colder air and as the freezing moisture droplets collide, the consequent electric charges produce thunderstorms. Lightning will also be produced.

However, it’s unusual for the exact conditions for thundersnow to occur - the layer of air nearest to the ground needs to be warmer than the layers above it, but still cold enough for snow to form.

Travel disruption

Drivers are being urged to take extra care on the roads. A cold snap and heavy fog at the start of the year were responsible for a number of motorway pile-ups that resulted in several deaths.

RAC spokesman Rod Dennis said: ”The fact that drivers in some parts of the country will be faced with strong winds, snow showers and icy stretches increases the chances of problems on the roads enormously.

“Commuters and those drivers planning longer journeys this week must heed the weather warnings and be prepared for tricky driving conditions and significantly extended journey times.“

The cold weather is set to last until the weekend, the Met Office said.

Freezing temperatures

The warnings come as continental Europe has been gripped by heavy snowfall and freezing temperatures, which had been blamed for several deaths in a number of countries.

Officials in Poland, where temperatures dropped to minus 20C, said the cold weather had killed at least 10 people in the past few days.

Parts of southern Italy were buried under a metre of snow and the fountains in St Peter’s Square froze over.