Depression over Bay of Bengal intensifies, cyclone warning issued at 9 Tamil Nadu, Puducherry ports

A depression is an organised low-pressure weather system with stronger circulation and winds than an ordinary low-pressure area. It can produce cloudy skies, rain and rough seas. Its development matters because falling pressure and strengthening winds may turn it into a tropical cyclone that threatens coasts and ports.

The system in the article began as a low-pressure system over the Bay of Bengal. It intensified into a depression, was expected to become a deep depression, then a cyclonic storm, a severe cyclonic storm and finally a very severe cyclonic storm. Over warm ocean water, heat and moisture can help a storm strengthen, while its circulation becomes more organised.

The IMD forecast this system to become a cyclonic storm by October 26 and a very severe cyclonic storm near the Andhra Pradesh coast by October 28. At landfall, winds were expected to reach 115–125 kmph, with gusts up to 140 kmph.

At 5.30 am on Sunday, October 25, the depression was over the eastcentral and adjoining southeast Bay of Bengal. It had moved southeastwards at 5 kmph during the previous six hours. Its position matters because the system was moving toward India’s eastern coastline while expected to strengthen.

The centre was about 440 km north-northwest of Sri Vijaya Puram in the Andaman Islands and 880 km east-southeast of Visakhapatnam. It was also 980 km east-southeast of Kakinada, 1,080 km east of Machilipatnam and 1,150 km east of Bapatla. The IMD expected it to turn west-northwestwards after moving south initially.

The system was forecast to reach the westcentral Bay of Bengal near the Andhra Pradesh coast by the morning of October 28. It was expected to cross the Andhra Pradesh and Yanam coasts between Bapatla and Visakhapatnam during the forenoon of October 28.

The cyclone was expected to reach very severe cyclonic storm strength before landfall. The IMD forecast maximum sustained winds of 115–125 kmph, with gusts up to 140 kmph. Such winds can make coastal travel dangerous, damage infrastructure and create hazardous conditions around ports.

Rainfall was also a major part of the threat. The article forecast heavy to very heavy rain across Puducherry, Karaikal and adjoining districts of Tamil Nadu. Puducherry had already received continuous rain since Saturday night because the northeast monsoon remained active, and several urban areas were waterlogged.

The precise rainfall amount was not given in the article, so the scale is described using the IMD’s “heavy to very heavy” category. Coast Road, Krishna Nagar and Laspet Sarum in Puducherry were already affected. Further rain could worsen waterlogging as the system approaches the coast on October 28.

Cyclone warning signals were hoisted at nine ports across Tamil Nadu and Puducherry after the Bay of Bengal system intensified into a depression. Ports need early warnings because approaching storms can make seas dangerous, disrupt vessel movement and threaten port workers, equipment and coastal facilities.

The signals were raised at ports including Chennai, Nagapattinam, Cuddalore, Karaikal, Pamban and Thoothukudi. The IMD expected the depression to become a cyclonic storm, then a severe and very severe cyclonic storm before reaching the Andhra Pradesh coast. This forecast gave authorities time to act before conditions deteriorated.

The warnings also reflect the system’s wider effects. Heavy to very heavy rain was expected in Puducherry, Karaikal and adjoining Tamil Nadu districts. Continuous rain had already caused waterlogging in parts of Puducherry, so port authorities and nearby communities faced both marine danger and flooding risk.

A powerful coastal cyclone can disrupt daily life across communities, ports, roads and cities. Strong winds can make travel unsafe and damage exposed buildings, infrastructure and port facilities. Heavy rain can overwhelm drainage systems, flood low-lying areas and interrupt transport and services.

The article gives an immediate example from Puducherry. Continuous rainfall since Saturday night caused waterlogging on Coast Road, Krishna Nagar and Laspet Sarum. The same weather system was expected to bring heavy to very heavy rain to Puducherry, Karaikal and adjoining Tamil Nadu districts, while ports raised warning signals.

The forecast landfall added to the risk. Winds were expected to reach 115–125 kmph, with gusts up to 140 kmph, as the cyclone crossed between Bapatla and Visakhapatnam. Further rainfall and strong winds could worsen urban waterlogging and create more dangerous conditions for coastal residents and port operations.

The India Meteorological Department classifies the system by its changing intensity and reports how that intensity is expected to evolve. In this case, the system progressed from a low-pressure area to a depression. The IMD then forecast a deep depression, cyclonic storm, severe cyclonic storm and very severe cyclonic storm.

Tracking combines the system’s location, movement and forecast path. At 5.30 am on October 25, the depression was 440 km north-northwest of Sri Vijaya Puram and 880 km east-southeast of Visakhapatnam. It had moved southeastwards at 5 kmph, but was expected to move south first and then turn west-northwestwards.

The forecast timeline showed strengthening by October 26 and October 27, followed by landfall on October 28. The IMD also estimated the likely landfall zone and winds. These updates supported warning signals at ports and helped authorities prepare for changing conditions.

The Bay of Bengal frequently supports cyclones because tropical ocean water provides heat and moisture, the energy that helps organised low-pressure systems strengthen. Its broad, warm waters can allow a disturbance to grow as air rises, pressure falls and winds become more organised. This general meteorological context explains why systems there can intensify quickly.

The article’s immediate example is a low-pressure system that became a depression and was forecast to reach very severe cyclonic storm strength. At the same time, the northeast monsoon remained active. Puducherry and neighbouring areas had received continuous rain since Saturday night, showing how seasonal moisture was already affecting the region.

The combination increased concern for coastal areas. The IMD forecast heavy to very heavy rain in Puducherry, Karaikal and adjoining Tamil Nadu districts, alongside strong cyclone winds. The article does not give a detailed explanation of the Bay of Bengal’s climatology, but it clearly links the active monsoon with ongoing rainfall.