An unusually shaped cloud off the north Norfolk coast has caused a fair bit of head scratching.

The long formation which resembled a flat mushroom was visible off Sheringham and Cromer on Saturday afternoon (March 6).

Sheringham resident Liz Dutton was among those baffled by the cloud as she took photos of it at 5.45pm and 6pm.

She said: "I’m always cloud watching, never seen anything like this before. I was in my house when I saw it, and rushed outside to take the pics."

Eastern Daily Press: An unusual cloud dominated the skyline off the north Norfolk coast.An unusual cloud dominated the skyline off the north Norfolk coast. (Image: Liz Dutton)

There was some speculation as to what type of cloud it was after Ms Dutton posted her photographs on social media, with suggestions it could have been a cumulonimbus capillatus or a cumulonimbus incus, also known as an 'anvil' cloud.

But Dan Holley, meteorologist for Norwich-based forecasters Weatherquest, had a different explanation.

Mr Holley said: "That looks like shallow cumulus that has tried to grow taller but hit the subsidence inversion and subsequently spread outwards.

"We're under high pressure at the moment, which forms when air sinks downwards through the troposphere, this creates an invisible 'lid' preventing clouds from growing any taller."

Mr Holley said 'anvil' clouds were thunderstorm clouds, but the atmosphere was very dry above 5,000ft yesterday, which would not have allowed thunderstorms to form.