Strong gales and heavy rain triggered by the first major cyclone of the year lashed the coastlines of India and Bangladesh on Monday, killing at least 16 people and cutting power to millions.
The winds had not stopped as night fell, with water rising in many places and overwhelming drainage systems, Bangladeshi climate expert Liakath Ali said.
"Many people are stranded - it will be another long night ahead with millions not having electricity or shelter," he said in a statement. "And people having no idea of how damaged their homes, land and livestock are."
Cyclone Remal is the first of the frequent storms expected to pound the low-lying coasts of the South Asian neighbours this year as climate change drives up surface temperatures at sea.
Packing speeds of up to 135 kph, it crossed the area around Bangladesh's southern port of Mongla and the adjoining Sagar Islands in West Bengal late on Sunday, weather officials said, making landfall at about 9 p.m.
More than 8.4 million people, including 3.2 million children, are at high health, nutrition, sanitation and safety risk, said Sheldon Yett, UNICEF Representative to Bangladesh.
At least 10 people were killed in Bangladesh, disaster management chief Mijanur Rahman told Reuters, adding some victims died en route to shelters or when their homes or walls collapsed, or drowned during the storm.
"People are usually very reluctant to leave their livestock and homes to go to cyclone shelters," he said. "They wait until the last minute when it is often too late."
State Minister for Disaster Management and Relief Mohibbur Rahman said the cyclone destroyed nearly 35,000 homes across 19 districts. An additional 115,000 homes were partially damaged.
"Many areas remain waterlogged, and fish enclosures and trees have been devastated. As more information becomes available, the full scope of the impact will be clearer."
Mangrove Forests Flooded
In West Bengal, four people were electrocuted, authorities said, taking the death toll in the state to six.
Bangladesh shut down electricity supply to some areas in advance to avoid accidents, while in many coastal towns fallen trees and snapped electricity lines further disrupted supply, power ministry officials said.
Nearly 3 million people in Bangladesh were without electricity, officials added. West Bengal authorities said at least 1,200 power poles were uprooted, while 300 mud huts had been razed.
Bangladeshi State Minister for Power and Energy Nasrul Hamid said in a Facebook post that Remal has caused extensive damage nationwide, urging people to be patient as repairs were under way.
"Our crews began repairing the lines as soon as the wind speed subsided," he said.
The cyclone also disrupted around 10,000 telecom towers, leaving millions without mobile service.
The rain and high tides damaged some embankments and flooded coastal areas in the Sundarbans, home to some of the world's largest mangrove forests, which are shared by India and Bangladesh.
Flooded roads disrupted travel in the Bangladeshi capital of Dhaka. Rain also flooded many streets in Kolkata, with reports of wall collapses and at least 52 fallen trees.
Kolkata resumed flights after more than 50 were cancelled from Sunday. Suburban train services were also restored.
Both nations moved nearly a million people to storm shelters, about 800,000 in Bangladesh and roughly 110,000 in India, authorities said.
Featured Video Of The Day
India Win Inaugural Women's U19 T20 Asia Cup, Beat Bangladesh In Final Fresh Reports Of Idol Vandalism In Bangladesh, 3 Hindu Temples Targeted India Lodges Protest With Bangladesh Over 'Map' Post By Muhammad Yunus Aide Is Safe Car Enough? Volvo Crash That Killed CEO, Family Sparks Big Question Pics: Rahul Gandhi's Family Lunch At Iconic Delhi Restaurant "Nothing Short Of Nightmare": Woman Misses Life Event, Slams Air India Public Sector Hydropower Company Hiring For 118 Posts, Check Details Delhi's Air Quality Turns 'Severe' Despite GRAP-4 Restrictions PM Modi Meets Yoga Practitioner, Other Influencers In Kuwait Track Latest News Live on NDTV.com and get news updates from India and around the world.