Mammatus Clouds - "True to their ominous appearance, mammatus clouds are often harbingers of a coming storm or other extreme weather system. Typically composed primarily of ice, they can extend for hundreds of miles in each direction."
Two climbers in California’s Yosemite national park make history as they reach the summit of what has been called the world’s hardest rock climb. Kevin Jorgeson and Tommy Caldwell, seen climbing here, scaled the half-mile section of exposed granite known as the Dawn Wall on El Capitan peak. Photograph: Corey Rich/Aurora Photos