"Everyone is amazed by it and it's the closest I've ever come to going viral," said photographer Curtis Christensen from New Orleans in the US.
Roll clouds most frequently form along the leading edge or "gust fronts" of a thunderstorm outflow yet they may form along the shallow cold air currents of some sea breeze boundaries and cold fronts. A roll cloud or Cloud Atlas is a low, horizontal, tube-shaped, and relatively rare type of arcus cloud.
