Roll Cloud

Published on 12 Nov 2025

• A rare “roll cloud,” a long, tube-shaped cloud formation, was recently spotted rolling over the coastline of Póvoa do Varzim, Portugal.

• A roll cloud, also known as volutus, is a rare meteorological phenomenon classified under arcus clouds, a group of low, horizontal cloud formations often linked to thunderstorms. 

• Roll clouds are distinct in their tube-like shape and the way they appear to rotate slowly along a horizontal axis, independent of the parent storm.

• The roll clouds usually form under very specific conditions:

• Warm, dry air ascends quickly because of strong surface heating (such as in a heatwave).

• This rising air collides with cooler, more humid sea breezes coming from the ocean.

• The difference between air masses produces turbulence and condensation and thus results in the roll-shaped cloud.

• Roll clouds can also occur due to coastal breezes, where cooler air from the land pushes beneath warmer sea air, triggering similar cloud formation.

• Though visually dramatic, roll clouds are usually harmless.

  
  

Keywords:

Roll Cloud Póvoa do Varzim Portugal arcus clouds Clouds climatology