Cyclone Amphan roared into West Bengal around 20 kilometre east of Sagar Island in the Sunderbans on Wednesday, packing winds gusting to a top speed of 185 kmph, triggering torrential rain and leaving a trail of devastation across a wide swath of the state, from deltaic regions to the urban neighbourhoods of Kolkata.

It brought a storm surge – a wall of ocean water that is often one of the main killers in major weather systems – that roared inland.

“The situation is more worrying than the coronavirus pandemic. We don’t know how to handle it,” West Bengal Chief Minister Mamata Banerjee told reporters late on Wednesday. “Almost everything is destroyed in the coastal villages of the state.”

Banerjee, who was assessing the situation from the state secretariat, said at least 10-12 people have died.

“The losses will be at three levels – loss to life and property because the storm was tremendous; loss to basic infrastructure, which will take months to leap back to normalcy, and thirdly, loss to livelihoods due to saline water intrusion and large-scale inundation. I have received reports of embankment breaks from Sagar Island, Ramganga, Hingalganj and a few other places. Many embankments are seeing overtopping of water because the rivers have swelled up, these will break in days,” said Tuhin Ghosh, director of the School of Oceanographic Studies at Jadavpur University.

Amphan, the most severe storm in the Bay of Bengal since the Odisha super cyclone of 1999, made landfall between 3.30 pm and 5.30 pm.

In neighbouring Odisha, at least two deaths were reported till Wednesday night. A two-month-old baby was killed in a wall collapse in the morning after heavy overnight rains in Bhadrak district. In another incident, a woman died in Balasore after an electric pole, uprooted by the storm, fell on her.

In Bangladesh, officials confirmed six deaths including a five-year-old boy and a 75-year-old man, both hit by falling trees, and a cyclone emergency volunteer who drowned.

Some three million people were left without power, Bangladesh officials said.

About 224.6 millimetres (0.7 feet) of rain fell from early Wednesday and winds up to 113 kmph (70 mph) lashed Kolkata, the capital of West Bengal.

Video shared on social media showed electricity transformers sparking and exploding in the wild weather. Some reports said that 5,500 houses were damaged in one West Bengal district.

The cyclone is expected to weaken as it moves north and northeast, and recede to a tropical depression by Thursday afternoon, the Indian Meteorological Department (IMD) said.

In southwestern Bangladesh, a five-feet-high storm surge broke an embankment and swamped farmland.

Bangladesh officials were particularly concerned about the damage to the Sunderbans, a UNESCO world heritage site famed for its mangrove forest and tiger population, which they said bore the brunt of the cyclone.

Houses “look like they have been run over by a bulldozer”, said Babul Mondal, 35, a villager on the edge of the Indian side of the Sunderbans.

The 1999 super cyclone left nearly 10,000 dead in Odisha, eight years after a typhoon, tornadoes and flooding killed 139,000 in Bangladesh.

In 1970, half a million perished due to Cyclone Bhola.