Extremely Severe Cyclonic Storm Sidr was an extremely deadly and devastating tropical cyclone that resulted in one of the worst natural disasters in Bangladesh. The fourth named and the deadliest storm of the 2007 North Indian Ocean cyclone season, Sidr formed in the central Bay of Bengal, and quickly strengthened to reach peak 1-minute sustained winds of 260 km/h (160 mph), making it a Category-5 equivalent tropical cyclone on the Saffir–Simpson scale. The storm eventually made landfall in Bangladesh on November 15, 2007, leading to large-scale evacuations. At least 3,447 deaths have been blamed on the storm, with some estimates reaching 15,000.