Orange clouds that appeared in the sky over Falkirk were likely caused by the nearby Ineos refinery, says STV weather presenter Jo Farrow.

The town's residents were treated to the sight early on Thursday evening, with photographers taking the opportunity to take some memorable snaps.

The clouds have been identified as anthropogenic, meaning they were artificially caused by human activity.

Jo explained: "A site like Grangemouth will always be releasing steam or water vapour clouds, with the current light winds, the clouds just remained in one lump, a mass above the town ready to reflect the evening sunlight.

"We've had high pressure for over a week now, which brings slowly descending air which stagnates. The air collects more particles, tiny bits of dust or smoke, and it is in these conditions that we get super sunset colours or in this case spectacular coloured clouds

"When they were hit by low-angle rays from the setting sun, you get a light display like the one in the photograph.

"So it's really an optical phenomenon - everything just came together at the right time."