Context: Cyclone Arnab, the first cyclone of the 2026 North Indian Ocean cyclone season, rapidly intensified over the Bay of Bengal before making landfall along the Andhra Pradesh–Yanam coast on October 28. Its development highlights the influence of El Niño on ocean temperatures, atmospheric circulation and cyclone tracks.
Key Highlights
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- Formation and intensification: Arnab originated as a low-pressure system over the southeast Bay of Bengal on October 23 and developed into a cyclone by October 26. It subsequently intensified into a very severe cyclonic storm, with sustained wind speeds of 125–135 kmph and gusts reaching 140 kmph.
- El Niño phenomenon: El Niño refers to the abnormal warming of surface waters in the equatorial and central Pacific Ocean. It alters global atmospheric circulation, rainfall patterns, temperatures and wind systems, influencing regional weather conditions.
- Impact on cyclone tracks: During El Niño years, tropical cyclones in the North Indian Ocean tend to form closer to the equator and may move towards the Andhra Pradesh and Tamil Nadu coasts rather than Odisha and West Bengal. Cyclone Hudhud in 2014 provides a historical example.
- Role of ocean temperatures: Between July and September 2026, sea surface temperatures in the Niño 3.4 region were reportedly 2–2.8°C above normal. Ocean temperatures of at least 26°C at depths of 50–100 metres can provide favourable conditions for cyclone formation and intensification.
- Complex atmospheric interactions: Cyclone intensity also depends on wind shear, convection, upper-ocean circulation, atmospheric boundary layers and air–sea interactions. El Niño alone cannot explain the cyclone’s behaviour.
- Impact and preparedness: Arnab caused heavy rainfall, uprooted trees and power poles, and disrupted electricity and transport. More than 1.8 lakh people were evacuated in Andhra Pradesh and Odisha before its arrival.
Significance
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- Climate science: Demonstrates the interconnectedness of the Pacific Ocean, atmospheric circulation and weather systems over the Indian Ocean.
- Disaster preparedness: Highlights the need for accurate forecasting, timely evacuation and resilient coastal infrastructure.
- Agriculture and livelihoods: Heavy rainfall, flooding and infrastructure damage can affect crops, fisheries, transport and local economic activity.
Concerns and Challenges
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- Rapid intensification: Sudden increases in wind speed reduce the time available for evacuation and emergency response.
- Forecasting uncertainty: El Niño is an influencing factor, not the sole determinant of cyclone intensity or trajectory.
- Coastal vulnerability: Dense settlements, fragile infrastructure and dependence on agriculture and fishing increase disaster risks.
Way Forward
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- Strengthen satellite monitoring, ocean buoys and real-time sea-temperature observations.
- Improve coupled ocean–atmosphere forecasting models and rapid-intensification prediction.
- Strengthen last-mile warnings, evacuation shelters, resilient power networks and local disaster-response capacity.
- Integrate climate variability into coastal planning, agricultural advisories and disaster-risk reduction.
Conclusion
Cyclone Arnab demonstrates how oceanic warming and atmospheric conditions can combine to intensify extreme weather. A science-based, anticipatory and community-centred disaster-management strategy is essential to minimise casualties and economic losses.
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