London-based Tropical Storm Risk said Cyclone Sidr was a Category 4 storm, packing winds of 135 knots and was heading due north on a course that would take it over the heavily populated southern coast. After this, it would move towards the capital, Dhaka.

Cyclones can cause immense devastation in disaster-prone Bangladesh, a low-lying country of more than 140 million people, particularly from storm surges that can rise as high as five metres. Weather experts say that severe cyclones cause land fall.

All rivers flowing into the Bay of Bengal along parts of the southern coast have all swollen and are still rising, water department officials said. “From my window, I can see tins ripped off the roofs and tree branches flying under the sky covered with thick clouds,’’ said Moulvi Feroze Ahmed, a local government official on St.Martin’s island in the Bay of Bengal, near the storm.

He added, “It looks like the sea is coming to grab us. It has been rough with high waves.The storm has already triggered a 3-foot high water surge.’’

Officials at Cox’s Bazar, a popular tourist destination, said they had evacuated nearly 200,000 people to about 600 government and private shelters and asked others to move on their own.

“The shifting process is continuing,’’ said Sajjadul Hasan, chief of the local district administration. People heading for shelters were taking food, clothes and their cattle with them.

Operations suspended
Chittagong and Mongla ports suspended operations on Wednesday and moved ships to safer areas, port officials said.

Storms batter the poor South Asian country every year. A severe cyclone killed more than half a million people in 1970, while one in 1991 killed 143,000 people.

Nearly 10 million Bangladeshis live along the southern coast, which usually bears the cyclone brunt. The area has shelters for only about half a million.