Almost half a million people have fled the eastern Indian coast, many leaving just hours before a "super cyclone" hit the country.

The vast weather system – cyclone Phailin – was generating winds of up to 220km/h (136mph) and forcing huge waves far inland before it struck the shores of Odisha and Andhra Pradesh states just after 9pm local time.

Aid and disaster management officials estimated that up to 12 million people lie in its path. They forecast widespread destruction and disruption though believed casualty levels would be "negligible" compared with those in 1999 when a storm killed 10,000 people. "The community is prepared, the government is prepared, the [NGOs] are prepared this time," said Manish Choudhary of the Indian Red Cross Society.

Choudhary said the group had set up 75 cyclone centres and five relief camps and was sending tarpaulins as well as water sanitation equipment to the disaster zone.

Even before landfall, coconut trees in villages along the coast had been bent and broken by the gusting wind. Electricity poles were brought down and roads were littered with debris.

A huge wave driven by cyclone Phailin comes ashore at Vishakhapatnam in India's eastern state of Andhra Pradesh. Photograph: AP

In the first reported deaths, two people were killed by falling trees while a third died when the walls of her mud house collapsed. Another two people died as the storm pressed inland, authorities said.

Reporters described terrified children clinging to their mothers as they sought shelter. Most towns along the coast were deserted but there were still some people trying to flee.

Authorities combed coastal areas for fishing communities unwilling to abandon their boats or others still in the danger zone. Police forcibly evacuated thousands, officials said. Some people took refuge in temples, others crammed into auto-rickshaws and headed inland.

Large numbers of troops were deployed and huge amounts of emergency food stockpiled, Indian media reported.

"This is one of the largest evacuations undertaken in India," said Shashidhar Reddy, vice-chairman of the National Disaster Management Authority, who estimated that more than 440,000 people had fled from their homes. Other estimates were as high as 550,000.

Indians were warned to seek shelter as cyclone Phailin approached. Photograph: Biswaranjan Rout/AP

Phailin was expected to bring a 3.4-metre (11ft) surge in sea levels when it hit the coast, meteorologists said. Forecasters also warned of extensive damage to mud houses, major disruption to power and communication lines, and the flooding of railways and roads. Flying debris was another threat.

"In a storm of this magnitude there is the potential for widespread damage to crops and livestock in the low-lying coastal areas and houses completely wiped away," said Kunal Shah, the head of the aid group World Vision's emergency response team in India.

London-based agency Tropical Storm Risk classed the storm in category five – the highest such rating. The US Navy's weather service said wind speeds at sea were gusting at 195mph (314km/h).

The storm was expected to cross half of India before losing strength over the central highlands of the vast country by the middle of next week.