Cyclone Arnab crosses Andhra coast; El Niño helps explain its path and strength
In one line: Cyclone Arnab struck the Andhra Pradesh and Yanam coasts as a very severe cyclonic storm on 28 October 2026, and El Niño helps explain why it formed so far south and turned towards Andhra.
Published 29 October 2026. Written by Pratidin from the reports linked at the end; every fact checked by a separate review before publishing. How we work
Cyclone Arnab, the first cyclone of 2026 in the North Indian Ocean basin, crossed the Andhra Pradesh and Yanam (Puducherry) coasts between Bapatla and Visakhapatnam in the early hours of Wednesday, 28 October 2026, as a very severe cyclonic storm. It began as a low-pressure area over the southeast Bay of Bengal on 23 October and became a cyclonic storm by 26 October, then intensified rapidly through the severe and very severe categories, with sustained winds of 125 to 135 km/h. The India Meteorological Department (IMD) advanced its landfall forecast from the forenoon to the early hours of 28 October because the storm moved faster than expected.
Unusually, the storm's centre stayed nearly stationary near Narsapur and Yanam from about 4 am, so it kept its intensity for at least six hours after landfall before weakening. Visakhapatnam recorded 217 mm of rain. Reports put evacuations across Andhra Pradesh and Odisha at more than 1.8 lakh people. The National Disaster Response Force said three people died and 31 homes were damaged. The IMD placed Andhra Pradesh and Odisha on red alert and Chhattisgarh on orange alert, and warned that the storm's remnants would bring very heavy rain to several States further inland.
The Indian Express links Arnab's track to El Niño, the abnormal warming of the central and eastern equatorial Pacific. Sea surface temperatures in the Niño 3.4 region were 2 to 2.8°C above normal from July to September 2026, and the 2026 El Niño is forecast to be among the strongest on record. As the southwest monsoon retreats, the monsoon trough shifts south; in El Niño years, changed winds and pressure near the equator tend to make North Indian Ocean cyclones form closer to the equator, so they are more likely to strike Andhra Pradesh and Tamil Nadu than Odisha and West Bengal. Experts caution that rapid intensification also depends on warm water at depth, low vertical wind shear and other factors, not El Niño alone.
Prelims facts
- Cyclone Arnab, the first North Indian Ocean cyclone of 2026, crossed the Andhra Pradesh and Yanam coasts between Bapatla and Visakhapatnam early on 28 October 2026 as a very severe cyclonic storm.
- It formed as a low-pressure area on 23 October and became a cyclone by 26 October, with sustained winds of 125 to 135 km/h at peak.
- It stayed nearly stationary near Narsapur and Yanam and kept its intensity for at least six hours after landfall.
- Niño 3.4 sea surface temperatures were 2 to 2.8°C above normal in July to September 2026.
- In El Niño years, North Indian Ocean cyclones tend to form at lower latitudes and track towards Andhra Pradesh and Tamil Nadu.
Quick recall
- Where did Cyclone Arnab make landfall?
- Andhra Pradesh and Yanam coasts, between Bapatla and Visakhapatnam, early on 28 October 2026.
- Category of Cyclone Arnab at landfall?
- Very severe cyclonic storm.
- Peak sustained winds of Cyclone Arnab?
- 125 to 135 km/h.
- When did Arnab's low-pressure area form?
- 23 October 2026, over the southeast Bay of Bengal.
- Niño 3.4 sea surface temperature anomaly in July to September 2026?
- 2 to 2.8°C above normal.
- Lower wind threshold of IMD's very severe cyclonic storm?
- 118 km/h.
- Minimum sea temperature usually needed for cyclone formation?
- About 26°C, extending 50 to 100 m deep.
- In El Niño years, where do North Indian Ocean cyclones tend to form?
- Closer to the equator, raising the odds of landfall in Andhra Pradesh and Tamil Nadu.
Prelims practice question
With reference to tropical cyclones in the North Indian Ocean, consider the following statements:
1. A very severe cyclonic storm, in IMD's classification, has maximum sustained winds of at least 118 km/h.
2. Sea surface water of at least about 26°C is a necessary condition for cyclone formation.
3. In El Niño years, cyclones in this basin tend to form farther from the equator than usual.
Which of the statements given above are correct?
- 1 and 2 only
- 2 and 3 only
- 1 and 3 only
- 1, 2 and 3
Show answer
Answer: (a) 1 and 2 only. Statement 1 is correct: IMD's very severe category begins at 118 km/h. Statement 2 is correct: warm water of about 26°C or more, extending to some depth, fuels cyclones. Statement 3 is wrong: in El Niño years they tend to form closer to the equator, which pushes tracks towards Andhra Pradesh and Tamil Nadu.
Use this in UPSC Mains: previous-year questions
Recurring theme: Tropical cyclones, El Niño and disaster preparedness in India
- How to use this
Shows El Niño can shift where Bay of Bengal cyclones form and strike, while other factors still govern intensity.
- With Niño 3.4 at 2 to 2.8°C above normal, Arnab struck Andhra Pradesh; El Niño-year cyclones tend to form nearer the equator and hit Andhra Pradesh and Tamil Nadu, not Odisha.
- Its rapid intensification also depended on warm water at depth and low vertical wind shear, not El Niño alone.
- How to use this
Provides a recent Bay of Bengal example of the warm-water and low-shear conditions that make these seas cyclone-prone.
- Cyclone Arnab grew from a low-pressure area on 23 October 2026 to a very severe cyclonic storm with 125 to 135 km/h winds.
- Rapid intensification of such storms depends on warm water at depth and low vertical wind shear.
- How to use this
Gives a live example of red and orange alerts guiding evacuation before a very severe cyclonic storm.
- For Cyclone Arnab, IMD placed Andhra Pradesh and Odisha on red alert and Chhattisgarh on orange alert.
- Early warnings helped move more than 1.8 lakh people; the NDRF reported three deaths.
Mains practice question
How does El Niño influence the formation, track and intensity of tropical cyclones in the Bay of Bengal? Discuss with reference to Cyclone Arnab of October 2026. (150 words)
Model answer
Cyclone Arnab, the first North Indian Ocean cyclone of 2026, crossed the Andhra Pradesh and Yanam coasts on 28 October 2026 as a very severe cyclonic storm, in a year with a strong El Niño.
Influence on formation and track
- El Niño warms the central and eastern equatorial Pacific; Niño 3.4 was 2 to 2.8°C above normal in July to September 2026.
- With the monsoon trough shifting south, El Niño-linked changes in winds and pressure make cyclones form closer to the equator.
- Such storms are likelier to hit Andhra Pradesh and Tamil Nadu than Odisha and West Bengal.
Influence on intensity
- Unusual warming of the North Indian Ocean adds energy; Arnab intensified rapidly to 125 to 135 km/h.
- It stayed nearly stationary near Yanam, keeping its strength for six hours after landfall.
Caveats
- Wind shear, ocean heat content and land interaction also matter.
Conclusion
El Niño years call for wider coastal preparedness in southern States.
The basics
Why this matters
Cyclones are a fixture of UPSC geography and disaster management questions. Cyclone Arnab adds a twist: a late-October Bay of Bengal storm that struck Andhra Pradesh rather than Odisha or Bengal, in a year of strong El Niño. Understanding why requires three static ideas: how cyclones form, how IMD grades them, and what El Niño does to the Indian Ocean.
How a tropical cyclone forms
A Tropical cyclone is a low-pressure system in which winds spiral inward and upward around a calm centre. It needs warm ocean water, moist air, enough distance from the equator for the Coriolis force to spin it, and low vertical wind shear so the storm column is not torn apart.
- 1Warm waterSea at about 26°C or more, extending 50 to 100 m deep, supplies heat and moisture
- 2Low-pressure areaRising moist air lowers surface pressure; Arnab's began on 23 October 2026
- 3OrganisationCoriolis force and low wind shear let thunderstorms spiral around a centre
- 4IntensificationArnab reached cyclone strength by 26 October and then very severe category
- 5LandfallCentre crosses the coast; Arnab did so early on 28 October 2026
How IMD grades storms
The IMD cyclone classification uses maximum sustained wind speed. The thresholds below are the lower limits of each category.
The El Niño connection
El Niño is the warm phase of the El Niño Southern Oscillation, when the central and eastern equatorial Pacific is unusually warm. In 2026 the Niño 3.4 region was 2 to 2.8°C above normal from July to September. In such years, post-monsoon cyclones in the North Indian Ocean tend to form at lower latitudes, so their tracks bend towards Andhra Pradesh and Tamil Nadu instead of Odisha and West Bengal.
- Often form farther north in the Bay
- Tracks frequently towards Odisha and West Bengal
- Tend to form closer to the equator
- More likely to strike Andhra Pradesh and Tamil Nadu
- Arnab crossed between Bapatla and Visakhapatnam
Why Arnab lingered
Most cyclones weaken quickly over land because they lose their supply of warm, moist air. Arnab's centre stayed almost stationary near Narsapur and Yanam, and it held its strength for at least six hours after landfall. Rapid intensification before landfall and slow movement at landfall are the combination disaster managers fear most.
Go deeper
Why it matters for UPSC
Cyclones appear in GS1 geography (formation, distribution), GS3 disaster management and Prelims (IMD categories, El Niño). Past Mains questions asked why cyclones are confined to certain seas and what IMD's colour-coded warnings mean.
The core idea
A Tropical cyclone needs warm water, moisture, Coriolis spin and low wind shear. The IMD cyclone classification grades storms by wind speed; Arnab reached the very severe category. El Niño in 2026 shifted where Bay of Bengal storms form, making an Andhra landfall more likely. Arnab's Rapid intensification and its slow crawl at landfall made it more dangerous than its category alone suggests.
Numbers and dates to remember
- 23 October 2026: low-pressure area forms
- 26 October: becomes a cyclonic storm
- 28 October, early hours: landfall between Bapatla and Visakhapatnam
- 125 to 135 km/h: peak sustained winds
- 217 mm: rain at Visakhapatnam
- 2 to 2.8°C: Niño 3.4 anomaly, July to September 2026
Where to go next
- Tropical cyclone: how these storms are born
- IMD cyclone classification: how storms are graded
- El Niño: the Pacific warming that shifts their tracks
- Rapid intensification: why some storms surge before landfall
Go deeper: Is El Niño the whole story?
What El Niño explains. In El Niño years the monsoon trough retreats south and winds and pressure near the equator change, so post-monsoon cyclones in the North Indian Ocean tend to form at lower latitudes. Their tracks then favour Andhra Pradesh and Tamil Nadu. With Niño 3.4 running 2 to 2.8°C above normal, 2026 fits the pattern, and Arnab crossed between Bapatla and Visakhapatnam. See El Niño.
What it does not explain alone. Rapid intensification depends on ocean heat content (warm water to 50 to 100 m depth), low vertical wind shear, a compact inner core and moist mid-levels. El Niño can warm the North Indian Ocean, but a single storm's behaviour reflects many factors.
Disaster management lessons. The IMD advanced its landfall forecast when the storm moved faster than expected, and authorities moved more than 1.8 lakh people. Three deaths were reported. The IMD cyclone classification grades wind speed, so warnings must also convey the rain and flooding risk of a slow-moving storm.
Exam angle. For a GS1 answer on Tropical cyclone distribution, add El Niño-linked shifts in genesis latitude as a modern example.
Tropical cyclone
The basic physics of the storm
In one line: A tropical cyclone is an intense low-pressure system over warm tropical seas, with winds spiralling around a calm eye.
Conditions for formation
It needs a large warm sea surface (about 26°C or more, extending some depth), enough Coriolis force to start rotation (so not within about 5 degrees of the equator), high humidity, a pre-existing low-pressure disturbance and low vertical wind shear. Released latent heat from condensing water vapour is its fuel.
In the Indian context
The Bay of Bengal sees more and stronger cyclones than the Arabian Sea, with peaks before and after the southwest monsoon. October to December is the main post-monsoon season, when Arnab formed.
Where to go next
IMD cyclone classification
How India grades storms by wind speed
In one line: The India Meteorological Department classifies low-pressure systems by maximum sustained wind speed, from depression to super cyclonic storm.
The ladder
Depression (31 to 49 km/h), deep depression (50 to 61), cyclonic storm (from 62), severe cyclonic storm (from 89), very severe cyclonic storm (from 118), extremely severe cyclonic storm and super cyclonic storm (222 and above). Systems are named once they reach cyclonic storm strength, using a list contributed by member countries of the WMO/ESCAP Panel on Tropical Cyclones.
Why it matters
Arnab, with sustained winds of 125 to 135 km/h, was a very severe cyclonic storm. Categories drive warnings, but they measure wind, not rainfall or how slowly a storm moves.
Where to go next
IMD cyclone classification: every story that connects to it (2)
El Niño
The Pacific warming that shifts Indian Ocean storms
In one line: El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), when the central and eastern equatorial Pacific becomes unusually warm.
How it works
Normally trade winds push warm water west towards Asia. In El Niño these winds weaken, warm water spreads east and global circulation shifts. Scientists track it with sea surface temperatures in the Niño 3.4 region. In India, El Niño is associated with weaker monsoons.
Why it is in the news
Niño 3.4 was 2 to 2.8°C above normal in July to September 2026, and the event is forecast to be among the strongest on record. In such years, post-monsoon cyclones in the North Indian Ocean tend to form closer to the equator and track towards Andhra Pradesh and Tamil Nadu, as Arnab did.
Where to go next
Rapid intensification
Why some storms surge in strength just before landfall
In one line: Rapid intensification is a sudden, large jump in a cyclone's sustained wind speed over a short period, often within a day.
What drives it
High ocean heat content (warm water extending 50 to 100 m deep), low vertical wind shear, moist air and a compact inner core let pressure fall and winds rise quickly. Cool water churned up from below, dry air or land interaction can stop it.
Why it is in the news
Arnab became a cyclone by 26 October and climbed rapidly through the severe and very severe categories. Rapid intensification close to the coast leaves less time for warnings and evacuation, which is why forecasters watch ocean heat as closely as surface temperature.
Where to go next
Take the 29 October 2026 quiz: 30 Prelims-style questions with answers