Swell Waves from Southern Indian Ocean Trigger Inundation Alert for Kerala, Tamil Nadu

The Indian National Centre for Ocean Information Services (INCOIS) has confirmed that high-period swell waves originating from the southern Indian Ocean have reached the coasts of southern Tamil Nadu and Kerala. The agency, responsible for providing ocean state forecasts during extreme weather conditions, said the waves have begun interacting with coastal regions, raising the risk of inundation in low-lying areas.

INCOIS observations off Kozhikode, Kanyakumari, and Thoothukudi have confirmed the presence of these swell waves. The system is expected to persist along the coast until the end of August 20, with wave surges and seawater inundation likely in low-lying coastal areas of Kerala, southern Tamil Nadu districts, and the Lakshadweep islands from the evening hours of Thursday, August 20, 2026.

Swell waves are long-wavelength waves generated by distant storms or strong winds, which can travel thousands of kilometers across the ocean. Even in the absence of local winds, these waves can cause sudden surges and flooding along coastlines, making them particularly hazardous for coastal communities.

Authorities have issued alerts for fishermen and residents in the affected districts. They have cautioned about intermittent gushing of seawater in nearshore and beach regions, particularly in low-lying areas. Fishermen have been advised not to operate small vessels near the coast of Kerala, and boat owners are urged to anchor their vessels at a safe distance from each other to prevent collisions and damage.

In response to the potential threat, all operational and recreational activities, including tourism activities on beaches and nearshore regions, have been suspended. The low-lying coastal areas are considered especially vulnerable, and INCOIS has stated that it is closely monitoring the situation.

The forecasts are generated using multi-model numerical ocean prediction systems, integrated with real-time data from moored buoys, wave rider buoys, and other ocean observing platforms, including those stationed in the southern Indian Ocean. This continuous monitoring allows authorities to issue timely warnings and minimize the impact of such events.

Kerala has previously declared tidal flooding as a State-specific disaster in February 2026, underscoring the frequent threat posed by such oceanographic phenomena. This latest alert comes amid growing concerns over the increasing frequency of extreme weather events along India's coastline, prompting experts to call for a redrawing of disaster management strategies to better address the challenges of climate change.

Residents in the affected regions are advised to stay away from the shoreline and follow instructions from local authorities. The public has been urged to remain vigilant and avoid venturing into the sea until the swell wave system subsides.