By Alastair Lawson
BBC News, Bhaupur, Bangladesh
A powerful cyclone has hit the coast of Bangladesh, with winds reported to be up to 240 kilometres (155 miles) per hour.
People have been warned of the dangers of the cyclone
Cyclones are not new to Bangladesh, but if the authorities are to be believed, they are now far less deadly.
In the 1970s thousands were killed during bad storms. The difference today - according to the government - is that the country is far better prepared for them.
"A most terrible cyclone is rushing towards the Bangladesh coast, but we are all set to deal with it," interim prime minister Fakhruddin Ahmed, said earlier on Thursday.
Over the last two decades, Bangladesh has embarked on a comprehensive programme to build cyclone shelters.
In addition thousands of volunteers have been trained to alert people to impending cyclones.
Boats plying rivers in the south of the country have been warned to keep off the water, and fishermen in the Bay of Bengal have received constant radio, newspaper and online warnings about the storm.
At least two days before the cyclone struck, volunteers and government officials toured villages in coastal areas of Bangladesh to warn people of the impending storm.
But the authorities face a huge task if they are to prevent a major loss of life.
Fishermen have been asked to stay away from the sea
There are several reasons for this apart from the severity of the storm itself, believed to be the worst in over 10 years.
Firstly, there is reluctance among people in rural areas of the country to abandon their homes, crops and livestock and take refuge in a cyclone shelter.
Many people refuse the advice of the authorities and choose to rough it out.
What is true on the land is also true on the sea.
Every time there has been a storm in recent years, fishermen always figure prominently in the casualty lists. That is because many choose to ignore cyclone warnings.
The reasons why they do have been attributed to the desire to get a bigger catch in the absence of competition from other boats and to a lack of education: they do not understand just how severe the storm is.
Secondly there are concerns that in a bad storm, there are not enough shelters for the number of people affected.
An estimated 10 million people live in Bangladesh's coastal areas and there is simply not enough room for all of them in the country's 500 or more shelters.
Bangladesh is one of the most densely populated countries in the world: nearly all the country is low lying and vulnerable to flooding.
The huge logistical exercise of dealing with such a large scale natural calamity is certain to stretch the resources of the authorities.
In the last big cyclone of 1991 winds of around 250kmh (155 mph) battered the south.
On that occasion, there was a six metre (20 foot) storm surge inland over a wide area, killing an estimated 138,000 people and leaving as many as 10 million homeless and sweeping away entire villages.
There are fears that there are not enough shelters
Water saturated the land several weeks after the storm had passed, and land erosion - always a problem in Bangladesh - resulted in many farmers losing everything.
Sixteen years ago most people died from drowning, with the highest mortality rates among children and the elderly.
A similar surge has been predicted for the current cyclone, along with equally powerful winds. That makes the role of cyclone shelters crucial.
But there are concerns that some of them are not in a good condition.
Often the biggest and strongest building in a rural area, some end up being used for community purposes which they were not originally designed for.
The older shelters in particular have become run-down. One seen recently by a team of journalists on board a BBC boat - which over the last 10 days has been chronicling the course of climate change in Bangladesh - had part of its roof missing.
But regardless of such lapses, officials remain confident that while the storm of 2007 may be of equal ferocity to its predecessors, the human cost will be far lower.
Over the next few days we will see whether those predictions are accurate.
Alastair Lawson was evacuated from the BBC boat currently engaged in charting the course of climate change in Bangladesh after it run aground in bad weather related to the cyclone.