Super cyclonic storm (IMD scale) | |
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Category 4 (Saffir–Simpson scale) | |
Super Cyclonic Storm BOB 01
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Formed | May 4, 1990 |
Dissipated | May 10, 1990 |
Highest winds |
3-minute sustained: 230 km/h (145 mph) 1-minute sustained: 230 km/h (145 mph) |
Lowest pressure | 920 hPa (mbar); 27.17 inHg |
Fatalities | 967 total |
Damage | $600 million (1990 USD) |
Areas affected | India |
Part of the 1990 North Indian Ocean cyclone season |
The 1990 Andhra Pradesh cyclone or the 1990 Machilipatnam Cyclone was the worst disaster to affect Southern India since the 1977 Andhra Pradesh cyclone. The system was first noted as a depression on May 4, 1990, while it was located over the Bay of Bengal about 600 km (375 mi) to the southeast of Chennai, India. During the next day the depression intensified into a cyclonic storm and started to intensify rapidly, becoming a super cyclonic storm early on May 8. The cyclone weakened slightly before it made landfall on India about 300 km (190 mi) to the north of Madras in the Andhra Pradesh state as a very severe cyclonic storm with winds of 165 km/h (105 mph). While over land the cyclone gradually dissipated. The cyclone had a severe impact on India, with over 967 people reported to have been killed. Over 100,000 animals also died in the cyclone with the total cost of damages to crops estimated at over $600 million (1990 USD).
On May 4, 1990, the India Meteorological Department (IMD) reported that a depression had developed over the Bay of Bengal about 600 km (375 mi) to the southeast of Chennai, India. During that day the system gradually developed further and became the subject of a tropical cyclone formation alert, by the Joint Typhoon Warning Center as it moved westwards under the influence of the subtropical ridge of high pressure. The depression subsequently intensified into a cyclonic storm early the next day, before the JTWC initiated advisories on the system and designated it as Tropical Cyclone 02B later that day. At this stage the JTWC only expected the cyclone to intensify marginally, before it weakened as it made landfall in Southern India within 72 hours. During May 6, the system started to move more towards the north-west because of a weakness in the subtropical ridge, as it continued to intensify and became a Very Severe Cyclonic Storm. This turn towards the northwest turned out to be more northerly than had been expected, which as a result allowed the system to stay offshore for longer than had been expected by the JTWC.
Over the next couple of days the system rapidly intensified before the JTWC reported early on May 8, that the system had peaked with 1-minute sustained windspeeds of 230 km/h (145 mph), which made the system equivalent to a category 4 hurricane on the Saffir–Simpson hurricane wind scale. At around the same time the IMD also reported that the cyclone had peaked as a Super Cyclonic Storm, with 3-minute sustained wind speeds of 235 km/h (145 mph) and an estimated central pressure of 920 hPa (27.17 inHg). By this time the system was located about 150 km (95 mi) to the northeast of Madras and was moving northwards slowly. Later that day as the ship Visvamohini moved through the systems eye region, it measured a central pressure of 912 hPa (26.93 inHg), which the IMD reported would be one of the lowest central pressures ever measured in the Bay of Bengal if it was correct. The system subsequently started to weaken and had become a Very Severe Cyclonic Storm by the time it made landfall during May 9, near the mouth of the Krishna River in southern Andhra Pradesh. The system subsequently moved north-westwards and gradually weakened further, before it was last noted during May 11, by both the IMD and JTWC.