Kolkata recently experienced torrential rainfall that left streets waterlogged, traffic disrupted, and daily life affected. Interestingly, this spell of heavy rain came without any cyclone in sight — raising the question: what caused such intense showers?

According to meteorologists, the downpour was linked to a low-pressure system over the Bay of Bengal, which intensified into a well-marked depression. These weather systems often mimic cyclonic conditions in terms of rainfall but do not develop the strong wind speeds and spiral structure of a cyclone. The system carried massive amounts of moisture inland, resulting in persistent, heavy showers over Kolkata and adjoining districts of South Bengal.

The monsoon trough, a semi-permanent low-pressure line stretching across the Indo-Gangetic plains, also played a role by drawing moist winds from the Bay. When these winds collided with land conditions in West Bengal, they triggered localized heavy rainfall. Meteorologists explain that such depressions are common during the peak monsoon months and, while less destructive than cyclones, can still cause flooding and disruption in urban areas.

Urban factors added to the impact. Kolkata’s poor drainage system and rapid urbanization led to severe waterlogging, turning moderate-to-heavy rain into a civic crisis. Experts warn that unless urban infrastructure is upgraded, even non-cyclonic rains will continue to paralyze the city.

In summary, the heavy rainfall in Kolkata was not due to a cyclone but the combined effect of a Bay of Bengal low-pressure system, monsoon trough activity, and local urban vulnerabilities. The episode highlights how monsoon dynamics can be as disruptive as cyclones, especially in cities struggling with drainage and climate resilience.