A rare phenomenon called a "roll cloud" covered Portugal beaches on Sunday, June 29 The tsunami-like formation shocked beachgoers, many of whom filmed the moment Scientists say the cloud was caused by ...

Check out this incredible roll cloud spotted off the coast of Portugal on Sunday. Roll clouds are most common with thunderstorms, but can also form when cooler air over the ocean sweeps under hot air ...

A viral video making the rounds on social media shows beachgoers in Portugal encountering an enormous and unnervingly tsunami-like cloud rolling in. Footage shows an enormous, foreboding wall of dark ...

Beachgoers in Portugal scrambled for cover over the weekend as the sweltering heat gave birth to a rare “tsunami roll,” an ominous wave of dark clouds over the water. Viral video of Sunday’s ...

A rare weather sighting occurred in Portugal as tourists and locals witnessed a one-of-a-kind cloud in the sky in recent days. (See the video at the top of this article.) A "tsunami" roll, also known ...

GRAND RAPIDS, Mich. (WOOD) — Humidity hovering over the surface of Lake Michigan helped to form a spectacularly skinny roll cloud Monday afternoon over Ottawa County. Roll clouds are rare, usually ...