NEW DELHI — A powerful cyclone whose spinning arms engulfed much of the Bay of Bengal weakened Sunday morning as it crashed into India’s eastern coast, flooding homes and roads throughout the region and disrupting electricity and communications.
The authorities evacuated about 800,000 people, one of the largest such evacuations in India’s history. The storm’s maximum sustained winds, which were approximately 124 miles per hour when the storm made landfall about 9 p.m. Saturday, had dropped to less than half that strength nine hours later.
At least five people were killed in the coastal city of Gopalpur because of heavy rain and high winds before the storm made landfall, officials said. The storm was expected to drop up to 10 inches of rain over the next two days in some areas.
The Indian predictions before the storm hit were less alarming than those from the meteorological authorities in the United States. Late Friday, the United States Navy’s Joint Typhoon Warning Center said the storm, then barreling across the Bay of Bengal, had maximum sustained winds of 161 m.p.h., with gusts reaching 196 m.p.h. — making it similar to a Category 5 hurricane, the most severe.
But once the storm arrived on land, its intensity was more modest, and Indian officials defended their more measured forecast as having been more accurate.
“We are not trying to downplay the intensity of the cyclone,” M. Shashidhar Reddy, the vice chairman of the National Disaster Management Authority, said at a news conference Saturday. “In fact, U.S. authorities are overplaying it.”
On Saturday, the Joint Typhoon Warning Center, in Hawaii, reduced its estimates, saying they showed maximum sustained winds of about 138 m.p.h. and gusts of up to 167 m.p.h.
L. S. Rathore, director general of the India Meteorological Department, termed the storm, named Cyclone Phailin, a “very serious cyclonic storm.” By Sunday, Mr. Reddy said, the storm is likely to be downgraded to a “serious cyclonic storm.”
Still, the true scope of natural disasters in India is often not known for days, given its large population and fairly weak central government. And powerful cyclones in the Bay of Bengal have a history of being particularly deadly because the geography funnels the storms into some of the most densely populated and poorest regions in the world. About 12 million people were in the storm’s path, according to Indian officials.
More than 10,000 people were killed 14 years ago when a powerful cyclone came ashore in roughly the same area, and more than 300,000 were killed in 1970 when a storm hit what is now Bangladesh. But disaster preparation arrangements are far better now, officials said.
Prime Minister Manmohan Singh said in a statement Saturday that he had been briefed on preparations for the storm and had directed that the central government extend all needed assistance to state officials.
In the Srikakulam district of Andhra Pradesh State, many mud homes and farms were destroyed, and uprooted trees blocked roads, according to officials there. About 30,000 people were evacuated from coastal villages in Andhra Pradesh.
K. Baliah, a district official involved in rescue efforts, said coastal residents had been reluctant to leave until they saw the sea rise. “At first they refused to leave their properties,” he said. Then, “when the water started to enter their communities around 2 p.m., the people decided themselves that they must leave.”
The surge accompanying the storm was expected to reach nearly 10 feet, weather officials said, which would cause heavy flooding across Andhra Pradesh and Odisha, another coastal state.
Service members from the country’s army, air force and navy were deployed to help in rescue and relief operations, said A. K. Antony, India’s defense minister.
The air force deployed C-130 aircraft, recently purchased from the United States, to help in the efforts, and the navy had diving teams with inflatable rafts deployed at important locations, Mr. Antony said. Military helicopters were also available for rescues, he said.
Pentayya Chintakayala, 33, a fisherman from a village near the port city of Visakhapatnam in Andhra Pradesh, said the fishermen of his village had stopped fishing and moved their boats inland, but were concerned that they could lose everything if the storm was as severe as predicted.
“What they tell us on television and what we see in the waves have nothing to do with each other,” he said. “Fishermen don’t always listen to the warnings, and 90 percent of the time that’s O.K., but 10 percent of the time the warnings are true, and we lose everything because we don’t believe them. Fishermen are stubborn like that.”
Mr. Chintakayala added that it was difficult to store fishing equipment very far inland, “because the boats are heavy and there isn’t much place to store them.”
Officials in the Visakhapatnam district were able to evacuate 21,500 people to relief camps by Saturday evening, including 3,500 inhabitants of flood-prone slums in the city of Visakhapatnam. But they said that they had often resorted to force, and that 30,000 more might have to be evacuated if the worst predictions came to pass.
“Basically the people are not willing to come to the shelters, because they are worried that they will lose their belongings,” said M. Venkateswarao, the district revenue officer. “They say that nothing bad will happen and that we are unnecessarily forcing them. But even if one person dies, it will look very bad for the district administration.”