Fallstreak hole: Unusual 'holepunch' cloud captured in East Midlands

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Fallstreak Hole in NottinghamImage source, Goff
Image caption,
A fallstreak hole, like this one in Nottingham, forms when part of the cloud layer forms ice crystals

The impressive winter sky has produced a visual spectacle that got photographers and BBC Weather Watchers reaching for their cameras.

A fallstreak hole was visible in the clouds above Nottinghamshire and Derbyshire on Tuesday.

The unusual formation appears as a large circular gap in a blanket of clouds.

Image source, linda
Image caption,
The fallstreak hole was visible in Riddings, Derbyshire
Image source, jimell
Image caption,
The Met Office says a fallstreak hole, like this one in Little Eaton, is formed when an aircraft passes through a cloud of supercooled water droplets

The Met Office says a fallstreak hole, also known as a holepunch cloud, form in clouds of supercooled water droplets below 0C but not yet frozen.

It said: "Aircraft punching through this cloud layer can cause air to expand and cool as it passes over the aircraft wings or propeller.

"This change in temperature can be enough to encourage the supercooled droplets to freeze and fall from the cloud layer in this distinctive pattern."

Image source, Ashfieldram
Image caption,
The view from Sutton-in-Ashfield

Analysis

By Alexandra Hamilton, BBC East Midlands Today weather reporter

It happens when you get water droplets that are supercooled, starting to turn to ice.

Around the outside the water droplets are still in their state of water whereas in the middle it has already started to turn to ice.

As they turn to ice they give off a tiny bit of heat and that's just enough to evaporate the surrounding water droplets and then you get this hole forming in the cloud.

Image source, Chris Cookman
Image caption,
Over the rooftops in Matlock, Derbyshire
Image source, Ady from Draycott
Image caption,
Under the clouds in Draycott, Derbyshire

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