Full Breakdown
Intensifying Northeast Monsoon Drives Heavy Rain Across Tamil Nadu
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Core Event
A vigorous northeast monsoon, reinforced by a low-pressure area over the southwest Bay of Bengal, has produced heavy to very heavy rainfall across Tamil Nadu and adjoining regions. The Regional Meteorological Centre warned that the system will sustain intense downpours until October 26, 2026. On Thursday, October 22, 2026, several districts recorded up to 15 cm of rain in 24 hours, with isolated locations such as Kanniyakumari, the Nilgiris and Coimbatore expected to see very heavy rainfall and squally winds of up to 50 km ph on Friday, October 23, 2026.
Background & Context
The northeast monsoon, active from October to December, has been amplified this year by an upper-air cyclonic circulation over the Gulf of Thailand and a “super El Niño” that raised Pacific sea-surface temperatures by more than 3 °C. Meteorologists noted that a fresh low-pressure system formed over the Bay of Bengal on October 21, 2026, with a second system likely on October 23, 2026. Both are projected to move northwestward, a typical track that limits their impact on Tamil Nadu but still brings widespread rain.
Data & Statistics
- Rainfall totals (24 h): MGR Nagar (Chennai) – 15 cm; Ezhudesam (Kanniyakumari) – 15 cm; Meenambakkam (Chennai) – 12 cm; Nungambakkam – 11 cm.
- Alert levels: Orange alerts for Tirunelveli, Thoothukudi, Kanniyakumari and the Nilgiris; yellow alerts for 26 districts including Chennai, Coimbatore and Ramanathapuram.
- River-level concerns: Central Water Commission warned of rising levels in the Bhavani, Noyyal, Aliyar, Siruvani, Moyar and other rivers through October 24, 2026.
Impact on Communities
The downpours triggered waterlogging in Chennai neighborhoods such as T Nagar, Saidapet and Velachery, and caused landslips on the Pollachi-Valparai Ghat Road in Coimbatore district. Schools were shut on October 21–22, 2026 across multiple districts, and Puducherry and Karaikal declared a full holiday on October 22, 2026. Fishermen in Thoothukudi were advised to stay ashore, and the Greater Chennai Corporation set up a control room to coordinate relief.
Official Statements & Responses
- Dr G S Sameeran, GCC Commissioner, linked the extreme precipitation to the “super El Niño year” and noted the IMD did not classify the event as a cloudburst.
- Rahul Gandhi, Leader of the Opposition, urged Congress cadres to assist relief operations, stressing care for senior citizens and vulnerable groups.
On-the-Ground Reports
Residents in Chennai reported waterlogged streets on Bazullah Road and Usman Nagar, while commuters in Thoothukudi faced disrupted bus services. In Coimbatore, boulders and mud fell on the Pollachi-Valparai Ghat Road, prompting temporary closures. A landslide near Parassala railway station in Kerala derailed a train but caused no injuries.
Conflicting Forecasts & Gaps
Most agencies forecast heavy to very heavy rain through October 26, 2026, but the IMD bulletin highlighted uncertainty about the exact track of the second low-pressure area expected on October 23, 2026. Some outlets projected isolated very heavy rainfall up to October 27-28, 2026, while others stopped forecasts at October 26, 2026. No definitive data on flood-related casualties or long-term infrastructure damage has been released.
Verbatim Quotes
- “The monsoon has already commenced... This is a super El Niño year, where the Pacific Ocean has warmed more than 3 degrees Celsius... We experienced very torrential rain on the midnight of 17th October... This led to heavy flooding,” — Dr Sameeran, commissioner
- “The IMD has said that it was not a cloudburst, but we received a huge amount of rain...” — The IMD