Cloud Tsunami A viral video making its rounds on social media shows geachgoers in Portugal encountering an enormous and unnervingly tsunami-like cloud rolling in. Footage shows an enormous, foreboding wall of dark clouds rapidly approaching a lush beach. It was frightening enough for plenty of beachgoers to pack up their belongings and seek shelter away from the beach. The wave, called a "roll cloud," appears when cold air comes in contact with high temperatures. Portugal, along with the rest of Europe, is suffering from a rare and deadly heatwave, hot enough to force Paris to close the summit of the […]