Rare ‘Roll Cloud’ stuns Beachgoers along Portuguese coast

Lisbon: Beachgoers in Portugal were treated to a surreal and stunning atmospheric display this week as a rare “roll cloud” stretched across the skies along parts of the Atlantic coastline.

The tube-shaped cloud, resembling a giant rolling wave in the sky, was spotted over beaches from Nazaré to Cascais, drawing crowds and a flurry of photos on social media.

The rare formation appeared early Monday morning, catching early risers and surfers by surprise. Witnesses described it as “otherworldly” and “mesmerizing” as it slowly drifted parallel to the shoreline.

“I thought it was the beginning of a storm or even a tornado,” said Marta Oliveira, a local photographer who captured the moment at Praia do Norte. “But then I realized it was something else entirely—beautiful and a bit eerie.”

Meteorologists from the Portuguese Institute for Sea and Atmosphere (IPMA) confirmed the phenomenon was a roll cloud, a low, horizontal cloud formation typically associated with cold fronts or outflow boundaries from thunderstorms. While harmless, they are extremely rare and only form under precise atmospheric conditions.

“These clouds are typically caused by a downdraft from a thunderstorm pushing out cooler air, which lifts warm, moist air ahead of it,” explained meteorologist Tiago Santos. “The result is a rolling tube of cloud that can span several kilometers.”

Roll clouds are often mistaken for shelf clouds but are unique in that they form independently from the main storm and rotate along a horizontal axis. They are most commonly seen in regions like Australia’s Gulf of Carpentaria, where the famous “Morning Glory” clouds appear seasonally.

This unexpected spectacle is the first reported roll cloud event in Portugal in over a decade, according to IPMA records.

While the skies cleared soon after, the awe-inspiring sight left a lasting impression on locals and tourists alike.
“This is why I always bring my camera,” Oliveira added. “You never know when nature will surprise you.”