The 1989 North Indian Ocean cyclone season was a below-average season in annual cycle of tropical cyclone formation. Despite this, the season had the second highest Accumulated Cyclone Energy in the basin on record behind only 2019 The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories. An average of five tropical cyclones form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.
Throughout the season, the IMD monitored ten depressions, three of which became cyclonic storms. The strongest storm of the year was Super Cyclonic Storm Gay. Crossing the Malay Peninsula into the Bay of Bengal on November 4, Gay became one of the most powerful systems on record in the basin, attaining an estimated pressure of 930 mbar (hPa; ). Collectively, the storms were responsible for at least 1,785 fatalities, 1,445 of which were due to the disastrous flooding triggered by the July Cyclonic Storm, and more than $25 million in damage.
Seasonal summary
Systems
Severe Cyclonic Storm BOB 01 (01B)
In mid-May, a monsoon trough situated over the Bay of Bengal began showing signs of cyclonic development. By May 20, synoptic data indicated the presence of a weak circulation; however, the system remained disorganized. Following a dramatic increase in convection and organization, the JTWC issued a Tropical Cyclone Formation Alert on May 23 and subsequently began monitoring the system as a tropical depression hours later. Initially, the depression tracked slowly towards the north-northwest before abruptly turning westward and slowing due to weak mid-level steering currents. During this time, the storm gradually intensified and was limited by northwesterly wind shear. By May 26, the storm turned northward and accelerated. Later that day, 01B attained its peak intensity with winds of shortly before making landfall in eastern India. The system quickly weakened once inland and was last noted on May 27 as a dissipating low.
Striking India on May 26, the storm brought wind gusts up to and torrential rains, amounting to , which caused widespread damage. The hardest hit area was Midnapore where more than 10,000 homes were destroyed. At least 17 people were killed in the district alone and more than 50,000 were left homeless. Communications across Orissa were severely disrupted as broadcast stations, government buildings, and hundreds of telephone poles were destroyed. Further inland, heavy rains from the storm triggered several landslides that killed at least two people in Darjeeling Hills. Throughout eastern India, 61 people were killed and more than 500,000 were left homeless by the storm.
In nearby Bangladesh, strong winds produced by the storm destroyed 500 homes across 11 villages. Areas devastated by a tornado a month prior were severely affected by the cyclone. In Tangail, a powerful tornado spawned by the storm destroyed 2,000 homes and killed 10 people. At least 60 people perished and 2,000 others were injured across the country. Offshore, 150 fishermen went missing during the storm and were feared dead. In the wake of the storm, widespread search and rescue missions took place in cities flattened by the cyclone.
Depression ARB 01 (02A)