Cyclone Nargis people, and the deadliest tropical cyclone in the North Indian Ocean since the 1991 Bangladesh cyclone, which killed at least 138,866 people. One aid worker claimed that the death toll from the cyclone and its aftermath might reach 300,000; if correct, Nargis was the second-deadliest cyclone ever and the fifth-deadliest natural disaster of the 20th century, after the 1931 China floods, the 1887 Yellow River flood, the 1556 Shaanxi earthquake, and the 1970 Bhola cyclone in Bangladesh. Myanmar's military leaders did not count the full death toll from Nargis (leaving the area shortly after it hit), and this led to
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,