Nearly 22,500 people were killed and 41,000 are still missing after cyclone Nargis ripped through the delta, Asia’s most devastating cyclone since 1991 when a storm killed 143,000 in neighbouring Bangladesh.

“We estimate upwards of one million people currently in need of shelter and life-saving assistance,” Richard Horsey of the United Nations Office of the Coordination of Humanitarian Affairs said in Bangkok after an emergency aid meeting.

“There are large swathes of the lower Irrawaddy delta completely under water. We are talking 5,000 square km under water. It’s a vast area,” he said.

The military Junta’s aid operation has moved up a gear with some helicopter drops into the region, but land convoys were nowhere to be seen, a witness in the malaria-infested swamplands of the delta said.

Aid experts say Myanmar’s ruling generals must overcome their distrust of the outside world and open their doors to a full-scale international relief operation if more victims are not to die of thirst, hunger and disease.

“With all those dead mostly floating in the water at this point you can get some idea of the conditions facing the teams on the ground. It’s a major logistical challenge,” Horsey said.

“The top priorities are water purification tablets, plastic sheeting, basic medical kits, bed nets and emergency food.”

Most of the victims were swept away by a wall of water from the weekend cyclone that smashed into coastal towns and villages.

One doctor in the town of Labutta said people clung to trees in a desperate fight for survival.

In Bogalay town alone, 10,000 people were killed, according to a town-by-town list of casualties and damage announced by the reclusive military government.

Political analysts and critics of 46 years of military rule say the cyclone may have long-term implications for the junta, which is even more feared and resented since last September’s bloody crackdown on Buddhist monk-led protests.

cyclone nargis

How it formed?

1. Cluster of thunderstorm gathers to form a low-pressure area, which draws in air and generates spin in a counter clockwise direction.

2. Warm ocean water fuels the transfer of heat and moisture to generate thunderstorms that rise upward.

3. Wind speed reaches over 120 km/h and a distinct eye forms in the centre. It starts moving towards land or cool water.

What are CYCLONES?

In meteorology, a tropical cyclone is a type of low pressure system which generally forms in the tropics. They are atmospheric circulation systems, which move heat from the equatorial region towards the higher latitudes

When do they occur?

• In the North Indian basin, storms are most common from April to December

• In the North Atlantic, June 1 to November 30, sharply peaking from late August through September

• The Northwest Pacific sees tropical cyclones year-round

What are they called?

• Cyclonic storm: In the North Indian Ocean (Myanmar, India, Bangladesh etc.)

• Hurricane: In the North Atlantic Ocean, North Pacific Ocean east of the dateline

• Typhoon: In the Northwest Pacific Ocean (Japan, Korea)