Explainer

The weather phenomenon that caused incredible lightning cloud like something from sci-fi film

People have been sharing their best pictures and videos of the lightning cloud that lit up the UK's skies overnight.

As the sun set on another hot and humid day, flashes of lighting could be seen illuminating the large cumulonimbus cloud in an impressive storm spectacle on Sunday 10 September.

The cloud of lighting in the video above was filmed from Ham Hill in Cheltenham, Gloucestershire at around 8.30pm.

But the huge black lightning cloud was also spotted by people across Bristol, Wiltshire and Herefordshire, with some even saying it looked like an "alien invasion".

While there were no thunderstorm warnings issued in the South West, a yellow weather warning covering much of northern England was in force from 2pm to 11.59pm.

The storm radar appeared to show that the lightning cloud spotted by people in the West Country was in fact on the north side of Bannau Brycheiniog National Park (formerly known as Brecon Beacons National Park), close to the border Herefordshire shares with Wales.

The storm radar appeared to show that the lightning cloud was on the north side of Bannau Brycheiniog National Park. Credit: Met Office

What causes the phenomenon?

ITV News West Country weather presenter and meterologist Charlie Powell said the weather phenomenon was caused due to the build up of an electrical charge in the cloud.

"During a thunderstorm the cumulonimbus cloud that forms is full of moving air, huge droplets of rain and hail.

"These all bump into each other and cause an electrical charge to build up, such that the cloud sort of turns into a massive battery with a collection of positive charge at the top, and negative at the base.

"When this imbalance gets too much an electrical charge is pushed out as a flash of lightning and a clap of thunder."

The dramatic lightning cloud could be seen illuminating the dark blue evening sky in Stow-on-the-Wold, Gloucestershire.. Credit: Martin Cox

He added that lightning won't always be seen striking the ground, as there are three main ways that lightning can behave.

"Sometimes the path of least resistance is between clouds, or even within the cloud itself if the thunderstorm is massive.

"That's what gives the incredible and eerie appearance of the cloud being lit from within with each lightning strike.

"The whole process then repeats itself multiple times over until the storm reaches the end of its lifecycle and runs out of steam," he said.