Peculiar clouds: Fallstreak cloud spotted in Cheshire

A hole punched through the clouds, that's what it looks like with this fallstreak cloud captured by a Weather & Radar user in May.

Daniel Vincoletto sent in the image above from Runcorn, Cheshire capturing a fallstreak in all its glory.

Fallstreak clouds are not technically clouds, but a formation which appears as a gap, or hole in the surrounding cirrocumulus or altocumulus clouds.

Both of these cloud types form at high, cold altitudes and contain supercooled droplets of water. This is water which can drop to as cold as -40°C without freezing thanks to the absence of other particles.

When aircraft pass through this cloud layer, it causes the surrounding air to expand and cool. The change in temperature can then cause the water droplets to suddenly freeze into solid ice crystals.

These ice crystals then fall from the sky as virga, or fallstreaks, which is precipitation that doesn’t reach the ground.

It might sound surprising, but the process of freezing actually gives off a tiny bit of heat. This heat is enough to evaporate the surrounding water droplets, leaving the sharply defined hole in the clouds that you can see in the image.

Have you ever spotted these fallstreak clouds before? We’d love to see your pictures, you can send them here.