CHENNAI: Tamil Nadu could face excess rainfall and floods this northeast monsoon; this could be followed by water scarcity, reduced reservoir inflows and drought stress next year caused by deficient or uneven rainfall. These are some of the preliminary views of an expert committee constituted by the State government to assess the impact of the Super El Nino system.
The committee, headed by Dr Sivananda Pai, head, Regional Meteorological Centre, Chennai, India Meteorological Department, submitted its preliminary report to Chief Minister C Joseph Vijay recently, calling for advance preparedness to deal with multiple and contrasting weather risks during 2026 and 2027.
The committee's assessment indicates excess rainfall over the southern peninsular region this October-December, and it has advised the government to prepare for heavy rainfall, urban flooding and riverine flooding during the northeast monsoon.
At the same time, the committee has cautioned that rainfall may not be uniform across the State. Areas experiencing deficient or uneven rainfall could face water scarcity, reduced reservoir inflows and drought stress. The committee has consequently recommended that preparedness should not focus only on either floods or drought, but it should address both possibilities.
The panel has also identified heatwave and heat stress during next year’s summer as a major area requiring preparedness. Its recommendations cover agriculture, horticulture, livestock, fisheries, coastal and marine systems, public health, energy and electricity demand, critical infrastructure and essential services.
The committee has proposed a three-stage preparedness framework short-term measures to be completed before the northeast monsoon, medium term measures before next summer and long-term measures to be implemented progressively over the next three to five years.
The committee has pointed out that historical rainfall records do not support treating El Nino solely as a drought-related phenomenon for Tamil Nadu. Historical evidence shows that El Nino years over the southeastern peninsula can be associated with normal as well as above normal northeast monsoon. Khole and De (2003) reported an 11% positive composite rainfall anomaly over the core southeastern peninsular region during El Nino years.
An IMD assessment covering 1940-2021 also found that northeast monsoon rainfall during El Nino years was excess in 28% of the years, above normal rainfall of 57% and only deficient in 15%.
The committee has cited 2005 as an example of how warm El Nino like conditions could coexist with extreme rainfall and flooding when accompanied by favourable synoptic conditions.
Tamil Nadu recorded 79% excess rainfall during October to December 2005, with repeated depressions and cyclonic systems over the Bay of Bengal triggering episodes of heavy rainfall.
The ECMWF (European Centre for Medium-Range Weather Forecasts) Seasonal Forecast System 5, issued in August 2026 for the October-December period, has indicated projects above normal precipitation over Tamil Nadu and neighbouring southern regions, with forecast anomalies broadly in the range of 50-200 mm in parts of the region.
The committee has said the model signal suggests an increased likelihood of normal to above normal northeast monsoon rainfall over Tamil Nadu, while also pointing to considerable spatial and temporal variability.
However, the report has cautioned that seasonal model forecasts should not be interpreted as predictions of individual rainfall events. Short duration extreme rainfall, cyclones and dry spells will continue to depend on evolving synoptic and regional-scale conditions.
The committee has recommended that the State adopt a multi-hazard, scenario-based and forecast-informed preparedness approach rather than preparing for only one possible outcome of the Super El Nino system.
The Disaster Management department has been advised to establish a TNDRRA-owned multi-hazard monitoring, early warning and early action system.
The proposed system should include hazard indicators, thresholds, predefined actions, nodal officers, data quality checks, Tamil first dashboards, SACHET dissemination and escalation and de-escalation protocols.
The committee has also recommended the use of drones for surveillance, search and rescue operations and rapid damage assessment.
District and block specific impact based warnings should be disseminated through SMS, radio, WhatsApp and social media, besides accessible formats.
While the immediate focus is on the possibility of excess rainfall and flooding during the 2026 northeast monsoon, the committee has also asked the government to prepare for water scarcity and reduced reservoir inflows in areas where rainfall remains deficient or uneven.
The committee's recommendations indicate that rainfall distribution will be as important as the seasonal rainfall total. Even if the State as a whole receives normal or above normal rainfall, areas receiving deficient rainfall could experience water stress.
The preparedness framework therefore includes measures for drought stress, reservoir management and water availability, particularly in regions where rainfall does not meet seasonal requirements.
The committee has also extended its preparedness framework into summer 2027, when heatwave and heat stress conditions could add pressure on water resources, agriculture, public health and electricity demand.
The School Education department has been advised to conduct awareness campaigns among schools, colleges and the public on weather-related risks and appropriate safety measures.
Schools have also been asked to include weather awareness and basic safety drills in their activities.
Before summer 2027, the committee has recommended seasonal uniforms or relaxed dress codes during periods of extreme heat, including light coloured fabrics and caps or hats.
School opening and related activities should be planned considering the possibility of an extended heat season and heat events. Outdoor sports activities and school timings should also be adjusted based on heat warnings.
The committee has further recommended introducing cool roofs and reflective paints or coatings in government and government-aided schools, with priority given to heat prone districts and urban heat island locations.
Over the long term, periodic maintenance of heat resistance measures in government schools, sustained heat risk awareness programmes and school based weather data collection have been recommended.
The committee has said preparedness should extend beyond rainfall and temperature. It has identified possible impacts on agriculture, horticulture and livestock, fisheries, coastal and marine systems, public health, energy and electricity demand, critical infrastructure and essential services.
It has also recommended that the government continuously monitor changing ENSO (El Nino Southern Oscillation) conditions, seasonal forecasts and actual weather impacts and periodically review its preparedness measures.
The committee's long term recommendations are to be progressively implemented over the next three to five years, with the objective of strengthening Tamil Nadu's climate and disaster resilience.
The expert committee comprises Prof Dr S Kanmani, Director, Centre for Climate Change and Disaster Management (CCCDM), Dr Balaji Narasimhan, Professor, Hydraulics and Water Resources Engineering Laboratory IIT Madras, Prof Dr Ramesh Ramachandran, Dr R. Venkatesan, Member, Marine Technology Society, Dr J.K. Patterson Edward, Director, Suganthi Devadason Marine Research Institute (SMRI) and R. Pradeep John popularly known on social media as Tamilnadu weatherman, besides chairman Dr Sivananda Pai.