Cyclone Fari barrelled into Bangladesh on Saturday after leaving a trail of deadly destruction in India, passing through hundreds of densely populated, low-lying communities along the Bay of Bengal, one of the most vulnerable regions to flooding in the world.

Major roads in the capital of eastern India’s Odisha state were scattered with trees and power lines, and the roof was torn off the city’s main railway station, after on Friday it was hit by the most severe storm on the Indian subcontinent in two decades.

Almost all thatched-roof and mud houses across four districts in the state were destroyed by the cyclone, which made landfall at about 8am on Friday morning and began migrating north-west towards the city of Kolkata.

Cyclone Fani: India evacuates 800,000 from coastal areas Read more

More than 1 million people, including at least 1,000 pregnant women, were moved from their homes into shelters.

Eight people reportedly died in India and Bangladeshi police said nine perished even before the eye of the storm rumbled over the border.

Rescue officials told the Guardian the dead included a teenager in Puri who was hit by a falling tree and a woman in an adjoining district who was struck by a collapsing wall.

“We have taken full precautions and my government is fully prepared to deal with the situation,” Odisha’s chief minister, Naveen Patnaik, told the Guardian. “I have learned of the casualties and am instructing officers to find out the reasons behind them.”

A powerful storm in Odisha, one of India’s poorest states, flooded hundreds of villages and killed more than 10,000 people in 1999, but more recent tolls have been greatly reduced by greater preparation, including better weather forecasting and early warning systems that can reach people in isolated villages.

Indian meteorological officials had categorised Friday’s storm as “extremely severe” when it reached Odisha, with maximum wind speeds of 175km/h, but said it was slowing as it travelled and had been downgraded to “very severe”.

Footage from Puri, a temple city of about 200,000 people that was the first to be hit by the storm, showed saturated palm trees flailing in deafening winds. Parts of the city were flooded, including the Puri-Konark Marine Drive, a major road that was submerged by about 1.5 metres of seawater.

“People have suffered a lot because the roofs of many houses are not concrete,” said Sanjukta Pannda from Kakatpur, a village in the Puri district, as the storm eased on Friday afternoon. “Those roofs have been wiped out and because of the rain there [are] lots of problems. The wind is slow right now but the rain is continuing.”

In Odisha’s capital Bhubaneswar, a city of more than 900,000 people, fallen trees and electricity poles blocked almost every major road after winds reaching almost 170km/h battered the city for at least four hours. Images from its main hospital, the All India Institutes of Medical Sciences, showed broken water tanks, damaged roofs and overturned trucks at its perimeter.

“All main roads are closed and 60% – or maybe more – trees and electric poles in the city have fallen,” said Bimal Pandia, a disaster mitigation officer with the charity Oxfam, which has a state office in Bhubaneswar. “Rescue workers are clearing the roads on a war footing.”

He said concerns were now turning to the possibility of unreported deaths in the state’s remote hinterlands and the possibility of flooding in coastal areas in the next few days.

“The devastation is quite serious in the interior areas,” Pandia said. “In the last major cyclone there were massive floods that happened for two days, so that apprehension is always there.”

The storm has interrupted India’s feverish campaign season with major figures from the ruling Bharatiya Janata party (BJP) including its president, Amit Shah, announcing they were suspending campaign rallies in adjoining states. Mamata Banerjee, the chief minister of West Bengal and a fierce rival of the BJP, also suspended campaigning for 48 hours.

PIB India (@PIB_India) The sound and the fury : here's what the landfall at Puri by #CycloneFani actually looked like..



Video by @PIBBhubaneswar pic.twitter.com/4GpvKFkRQ3

All flights out of Bhubaneswar were cancelled on Friday and Kolkata airport was closed from 9.30pm on Friday evening until 6pm on Saturday. Tourists were evacuated on three special trains on Thursday but nearly 150 other railway services have been suspended.

Hundreds of disaster management personnel have been deployed across the state, which has closed its schools and colleges and suspended leave for doctors and health officials for the next fortnight. The Indian army, navy and air force were on alert to assist with rescues.

Nearly 5,000 shelters were set up in Odisha for the evacuees. Police in the state posted pictures on social media showing officers folding their hands in a mark of respect to persuade reluctant people to cooperate and move to safer ground.

Facebook Twitter Pinterest Stranded passengers rest inside a railway station after trains between Kolkata and Odisha were cancelled due to Cyclone Fani. Photograph: Rupak de Chowdhuri/Reuters

Pandia said Oxfam was among the civil society groups working with the government and had prepared enough material to quickly reconstruct 5,000 houses.

The cyclone’s name, Fani, is Bengali for the hood of a snake. The word cyclone itself is said to be derived from the Greek word meaning “coiling of a snake”, and was coined by the British administrator Henry Piddington while he was stationed in Kolkata, then Calcutta, during colonial rule.

Fifteen of the 20 deadliest-ever storms have formed in the Bay of Bengal, where the combination of poor quality housing, dense populations and flash flooding frequently lead to high casualties. The Bhola cyclone that hit Bangladesh in 1970 killed more than half a million people.

PIB in Odisha (@PIBBhubaneswar) FANI impact in Puri pic.twitter.com/s88pqKhLbR

But Indian governments had vastly improved their responses to such disasters, said Mihir Bhatt, the founder and director of All India disaster mitigation institute.

He said early warning systems were now geared to reach “the last mile and the last place”, people were promptly moved to shelters or safer ground within their villages, and state governments – which had previous prepared for disasters in isolation – were now sharing information and coordinating tactics. “This is new and has played an active role in reducing the death toll,” Bhatt said.

More than a million people were evacuated from Odisha during a 2013 storm in a move that is thought to have saved thousands of lives. Around 50 people were killed by that cyclone.

Bhatt said India’s recent election may have also contributed to increased preparedness among the central and state governments. “There is an environment of showing you are performing and doing it,” he said.