Cyclone Nargis though after beginning a steady eastward motion, Nargis rapidly intensified to attain peak winds of at least 165 km/h (105 mph) on 2 May, according to IMD observations; the JTWC assessed peak winds of 215 km/h (130 mph), making it a weak Category 4 cyclone on the SSHS. The cyclone moved ashore in the Ayeyarwady Division of Myanmar at peak intensity and, after passing near the major city of Yangon (Rangoon), the storm gradually weakened until dissipating near the border of Myanmar and Thailand. Nargis is the deadliest named cyclone in the North Indian Ocean Basin, as well as the
Cyclone Nargis of low vertical wind shear, before it was classified as a depression by the India Meteorological Department early on 27 April. Initially, the depression moved westward and was classified as a deep depression by the IMD, before the United States Joint Typhoon Warning Center (JTWC) initiated advisories and classified the storm as Tropical Cyclone 01B later that day. The system subsequently started to move north-westwards under the steering influence of an anticyclone and an upper level ridge of high pressure. At 0000 UTC, 5:30 AM Indian Standard Time, on 28 April, the IMD upgraded the system to Cyclonic Storm Nargis,