Imagine the population of a city, about the size of Liverpool or Bristol, being relocated into a damp, rainy countryside without drinking water, shelter, food or latrines. Imagine the logistical challenge of building all the necessities of a safe life before hunger takes a deadly toll, before diseases break out and before the strong prey on the weak.
That is what has happened over the last six weeks in Bangladesh. Over half a million people have walked for days from their homes in Myanmar, crossed rivers and marshes, over the border into Cox's Bazar, and then settled on barren hills, in forests and on rice fields.
Over the last two weeks the majority of them have moved into makeshift camps. The camps are a hive of activity, with endless footsteps squelching through muddy footpaths, winding up and down hill slopes through miles of shelters made of plastic sheeting.
Behind this plastic sheeting are the stories that bring this tragedy to life. The successful farmer who built a house for himself and his family that was the pride of the village, and who ten days ago watched it torched with all his belongings, and is now left with nothing but the clothes on his back. The mullah who used to call his villagers to pray, and who last week watched his mosque burned down. The elderly man crouching in pain on the ground from an untreated sickness, his wife clutching her ribs broken by a gun butt, lamenting that their elder children are lost. The young widow, so afraid to step out from behind her plastic sheets that she hasn't eaten in three days.
Their crises are all personal, but the narrative of their last weeks is common. They watched their homes destroyed. They fled in panic. They carried nothing with them. Their families, their communities, have abandoned their homes and are now scattered across a maze of giant, mud soaked camps in a neighbouring country.
The government of Bangladesh and major aid agencies, such as Red Cross Red Crescent, now have the task of servicing the basic needs of half a million people who have become totally dependent on aid. This is not just about the logistics of providing safe drinking water, latrines, food and shelter, it is about navigating the hidden risks and vulnerabilities that exist in a massive social network of a displaced and traumatised population.
Even a quick walk through the camps is enough to see that the majority of people sitting behind the plastic sheeting are women. Early assessments are revealing that some of these women are not eating or drinking in order avoid the need to step out and go to toilet or wash. How can these chaotic hill camps, without electricity or privacy, be made safe for them and their children?
This is challenging because there is so little we understand about how families and communities have been broken and reconfigured by this displacement, who that has made vulnerable and where the threats may come from. The aid workers flying into Bangladesh are encountering serious language barrier challenges, as well as cultural ones.
One answer is to move as many people as possible into better organised, safer camps. This is the plan of the Bangladeshi government. But it will take time, and the current plans will accommodate at best only half of the new arrivals.
Then there are the costs to consider. The displaced communities will not be allowed to work while the conditions of return are negotiated. So they will be forced into dependency. The cost of sheltering, feeding and providing medical care to such a population is extensive. Perhaps a wave of international solidarity will raise enough to sustain support for a year. But if past experience is anything to go by, a year will not be enough, so financial commitments will have to be longer.
The people living in the camps know that there are no humanitarian solutions here, only political ones. But humanitarian organisations have a duty to help the government of Bangladesh provide as much dignity and protection as possible to these people: a people whose fate nobody could envy.
Donate to the Disaster Emergency Committee's Emergency Appeal for people fleeing Myanmar at dec.org.uk or by calling 0370 60 60 610.