Hunker down: On Cyclone Arnab, its landfall

Landfall is the point when a tropical cyclone’s centre moves across a coastline onto land. It matters because the storm’s strongest winds and heaviest rain can then affect communities directly. Forecasting the timing helps authorities evacuate people, close dangerous transport routes, and protect infrastructure before conditions worsen.

Cyclone Arnab made landfall on October 28 as a very severe cyclonic storm. Its core winds reached 125-135 kilometres per hour. The storm moved faster than expected toward the coast, stalled briefly, and then began landfall several hours before the India Meteorological Department had predicted. The process occurred in the middle of the night.

That earlier timing narrowed the possible evacuation window for high-risk settlements. Andhra Pradesh reported heavy rain and disruption, while southern Odisha faced continuing threats from rain in Arnab’s outer circulation. The article links the relatively low death toll to disaster-management operations, but says transport closures, power cuts, and other precautions created wider social and economic costs.

Arnab was classified as a very severe cyclonic storm when it made landfall. Its core wind speeds were 125-135 kilometres per hour. That level of wind can damage property, disrupt transport, bring down power lines, and endanger people outside or in vulnerable structures. The storm’s scale was also shown by its heavy rainfall and broad circulation.

More than 100 mm of rain fell over parts of Anakapalli, Visakhapatnam, Kalingapatnam, Kakinada, and Machilipatnam in Andhra Pradesh. The cyclone then left moisture in its outer circulation. That moisture was expected to move over southern Odisha, bringing further rain even after the centre had crossed the coast.

Arnab therefore affected more than its landfall point. Andhra Pradesh faced wind, rain, transport interruptions, and power cuts. Odisha’s Ganjam, Gajapati, Rayagada, Koraput, Malkangiri, Nabarangpur, and Kalahandi districts received alerts. The article also notes that Sundargarh farmers hoped for useful rain after a dry month.

Rapid intensification means a cyclone becomes much stronger over a short period. It matters because forecasts must estimate not only where a storm will go, but also how powerful it will become and when it will arrive. Small timing errors can affect evacuation orders, shelter preparation, transport shutdowns, and emergency deployment.

Arnab intensified rapidly before landfall, and some models did not anticipate how strong it would become. It also moved faster than expected toward the coast. After stalling for a time, it began the landfall process several hours before the IMD had forecast. The early landfall happened in the middle of the night, when reaching exposed communities is harder.

This combination created a narrower safety window for district authorities. They had less time to identify high-risk settlements, move residents, and secure loose objects or infrastructure. The article credits disaster-management operations with limiting deaths, while warning that forecasts and governance must account for storms that strengthen or change speed faster than expected.

Landfall does not instantly end a cyclone’s hazards. A storm can leave moisture in its outer circulation, and that moisture may continue producing heavy rain over land. The danger becomes greater where earlier monsoon rain and flooding have left rivers, fields, and soil with limited capacity to absorb more water.

The article says southern Odisha may receive rain and water from Arnab’s outer circulation. The State had experienced its fourth wettest monsoon in history, and some areas had recovered only in patches from earlier flooding. Further extreme rain could therefore cause additional flooding even at lower rainfall levels. Hilly terrain also faces a risk of slope failures.

The IMD issued alerts for Ganjam, Gajapati, Rayagada, Koraput, Malkangiri, Nabarangpur, and Kalahandi before the rainbelt moved farther north. Farmers in Ganjam and Puri feared prolonged inundation would destroy paddy crops. The article says Ganjam had already lost 33% of crops by October, increasing the possible economic damage.

Disaster-management measures protect lives by reducing people’s exposure before dangerous conditions arrive. Evacuating high-risk settlements moves residents away from flooding and wind damage. Closing roads, flights, schools, and offices keeps people from travelling into hazardous conditions. Power cuts can reduce risks from damaged or loose electrical wires.

During Arnab, authorities used these measures in Andhra Pradesh and Odisha. Road connectivity and flights were suspended, schools and offices closed, and electricity was cut in places to minimise danger. The article attributes the early reports of no deaths in both States to disaster-management operations, although Andhra Pradesh Chief Minister N. Chandrababu Naidu later said five people had died in Andhra Pradesh.

These actions carry real costs. Families may lose access to work, services, markets, and transport. Farmers can suffer when crops remain underwater, while damaged property and infrastructure create longer-term losses. The article says States must include these social and economic disruptions in post-storm assessments and move toward a zero-disruption approach.

Soil normally absorbs and stores some rainwater. When it is already saturated, that storage space is largely gone. New rain then runs across the surface or collects in low areas more quickly. This can raise flood levels even when the later rainfall is less intense than the rain that caused the original flooding.

The article says parts of Odisha had not fully drained after the fourth wettest monsoon in the State’s history and repeated flooding. If Arnab’s outer circulation brings extreme rain, the water may have nowhere to go. Fields could remain inundated, and hilly terrain could experience slope failures because saturated ground is less stable.

This creates a chain of risks for people, crops, and infrastructure. Farmers in Ganjam and Puri worried about prolonged water covering paddy fields. Ganjam had already lost 33% of crops by October. The IMD’s alerts across seven districts show why continued monitoring and drainage planning remained important after landfall.

In general, tropical cyclones form over very warm ocean water when rising moist air lowers pressure near the surface. As water vapour rises and condenses, it releases heat, which can power more rising air and stronger circulation. If conditions remain favourable, this feedback can make a storm intensify rapidly. The article does not detail this formation process, but it reports Arnab’s rapid strengthening.

Arnab intensified quickly before landfall, and some forecast models failed to predict how strong it would become. It also moved faster than expected, briefly stalled, and then began landfall several hours before the IMD forecast. These changes affected both the predicted intensity and the predicted arrival time, especially for nighttime evacuations.

Forecasting is difficult because storm strength and movement can change as the storm interacts with the ocean and atmosphere. In Arnab’s case, the result was a shorter window for district authorities to evacuate high-risk settlements. The article’s wider lesson is that disaster planning must prepare for rapid changes, not rely only on one forecast.