These amazing pictures were shot by two photographers - Mike Olbinski and Blaine Coury - in Arizona. These time-lapse videos show a wall of dust moving through the city of Phoenix in Arizona. Sandstorms like this happen during the region's monsoon season, which is underway. They occur over desert land and can reach thousands of feet into the air, spurred by strong winds. The dense cloud dramatically reduced visibility, grounding flights at a major airport and leaving thousands without electricity. PS A haboob is a type of intense sandstorm commonly observed in arid regions throughout the world.