A weather expert has told how a series of factors led to heavy fog at the Sheppey Crossing yesterday - and why he isn't surprised it caused such a huge accident.

Darren Prescott explained the Isle of Sheppey is more prone to fog because of its marshland areas.

The 33-year-old said there were several contributing factors that caused the thick mist - and sparked a huge pile-up of 130 vehicles.

He explained a lot of moisture is needed to form fog and it occurs when the air temperature is at or very close to the dew point – the temperature the air has to cool to for dew to form.

Yesterday the dew point was at around 16C, which is why it has been so muggy and this - added to the warm sea breeze which is coming from the North Sea - has drawn in more moisture than normal.

Because the nights have seen calm conditions, the air near the ground has been cooling quickly and marshland is more prone to fog anyway due to an abundance of moisture.

As a result of all those factors, really dense fog was formed and because of a lack of wind it became consistent and only cleared once the temperature rose above the dew point.

Mr Prescott, who monitors the weather from his home in Bay View, said: "Although fog can form for a variety of reasons, this was a result of warm, humid air, an afternoon sea breeze on Wednesday and calm winds on Wednesday night.

"It was among the thickest I've seen with visibility varied – down to about 50ft in the worst areas across the marshes and around Queenborough.

"I thought as I drove to work early on Thursday that it was pretty foggy and that an accident on the bridge was a possibility."

Mr Prescott, who works at the Westlands School in Sittingbourne, added he does not believe street lighting would have prevented the crash as it just makes the fog itself brighter and does nothing to improve visibility.

Like other drivers who used the road that morning have said, Mr Prescott says he saw a few people driving with no fog or sidelights.

"I'm relieved there were no fatalities and hopefully it'll reinforce that keeping a safe distance and using fog lights is important," he added.

"Hopefully those who are injured will make a swift recovery."

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