Many live in flimsy little shacks that cling to hills with just blue tarpaulin to protect them from the wind and rain in Cox's Bazar, Bangladesh.
This article was supplied as part of Stuff's partnership with Unicef NZ.
Having escaped persecution in Myanmar, hundreds of thousands of Rohingya refugees in Bangladesh are now at risk from the wild storms hammering the region.
This week a three-year-old boy became the first casualty of Bangladesh's monsoon season, as torrential rains caused chaos in the crowded camps of Cox's Bazar, where almost a million Rohingya have found refuge.
Rohingya refugee children wade through flood waters surrounding their families' shelters following an intense pre-monsoon wind and rain storm in Shamlapur Makeshift Settlement, Cox's Bazar district, Bangladesh on May 20, 2018.
The young boy was crushed in his sleep, and his mother badly injured, when a mud wall collapsed onto his family's shelter.
Another two people have since been killed. They were all among the hundreds of thousands of families who had escaped murder, rape, and violence in Myanmar, to seek safety across the border in Bangladesh.
For weeks, tens of thousands of refugee families have been preparing for the monsoons, securing their shacks, digging new latrines, carving out channels for the inevitable torrents, and relocating to higher ground.
Rohingya refugee children struggle with the mud collecting on a retaining wall during the first days of monsoon rain in Kutupalong Camp, Cox's Bazar. Much of the infrastructure of the camps is eroding as the rain falls. Deforestation has left the sandy ground unstable. Since an outbreak of violence began on 25 August 2017, approximately two thirds of a million Rohingya people have sought refuge in neighboring Bangladesh. More than half of them are children. UNICEF and partners are working to provide for the needs of this enormous refugee population who are all the more vulnerable during the rainy season. During the monsoon season, which lasts from June to September, the overall health and wellbeing of Rohingya refugee children is affected. Increase risk of infectious disease, poor water and sanitation hygiene, and injury impact children whose immune systems are already weakened by acute malnutrition. In May 2018, UNICEF estimated that more than 100,000 people, including approximately 55,000 children, are at risk due to floods and landslides. It?s possible that this figure could go up to 200,000 people depending on the intensity of rains.
"Lots of people moved very quickly," said Martin Worth, Unicef's head of Water, Sanitation and Hygiene.
"Now they are living in flimsy little shacks that are clinging to hills with just blue tarpaulin to protect them from the wind and rain. The conditions are crowded. The potential for disease outbreak is really high. I'm very worried."
"This is going to be a challenge," he says. "We have a refugee situation but with cyclone season coming we could also have a natural disaster on our hands. We are doing everything in our power to be prepared and able to respond."
On June 5 2018 in Bangladesh, a boy carries bricks from his old shelter to a new camp.
The makeshift cities of Cox's Bazar stretch for kilometres - every hill and valley crowded with crude, hand-built shelters.
Even those perched on the higher ground aren't safe, with the torrential rains regularly causing hillsides to slip away, taking homes, belongings, and people with them.
Throughout the sprawling settlements, homemade tents cling precariously to the muddy hillsides, and crowd the muddier gullies.
The first powerful monsoon rain drenches Shamlapur Rohingya refugee camp. As the camp is located close to the shoreline of the Bay of Bengal, it is one of the most vulnerable to flooding.
Even those homes perched on the higher ground aren't safe, with the torrential rains regularly causing hillsides to slip away, taking homes, belongings, and people with them.
Men, women and children have been working relentlessly to prepare, often armed with little more than crude tools, bamboo, and tarpaulins.
Many of the Rohingya refugees have moved more than once and are weary of the process.
Children watch as a adult clears soil from a drainage ditch around their shelter on the edge of a steep slope above a road. Rohingya refugees struggle through the mud during the first days of monsoon rain in Kutupalong Camp, Cox's Bazar.
Already, almost 19,000 refugees living in high-risk areas have been relocated to safer land, with another 18,000 to be relocated by the end of the month.
Since the first of the heavy downpours of monsoon season on Monday, a further 300 families have been forced to evacuate. And in the tightly packed refugee communities of Cox's Bazar, safe land is at a premium.
Even those shelters that have been strengthened are unlikely to be able to withstand high winds, and around 75% of the ramshackle bridges scattered throughout the settlements are unlikely to stand up to the constant battering of a heavy storm.
An aerial photograph of Kutupalong makeshift camp for Rohingya refugees in Cox's Bazar district in Bangladesh.
With evacuation options near non-existent, a catastrophe is likely should a tropical cyclone strike the region.
The rain also causes problems for agencies trying to deliver life-saving humanitarian aid.
The main road running through the settlements turns to mud in heavy rain, making it near impossible to deliver urgent, life-saving aid.
Patricia Mugenyi, Unicef's Supply Logistics Specialist, says staff constantly have their eyes on the weather.
"We have a preparedness plan in place in case the roads are washed out and we have no accessibility to the camps," she said. "I also need a back-up plan if there is a landslide. Then I need to know what I will do if there is another mass movement of the refugees in search of safer places."
The season ahead looks long and grim. Monday's chaos came after 230mm of rain fell in just 24 hours. Even more was expected this week, and the monsoon season still has months to run.
Of the one million Rohingya refugees living in Bangladesh, around half of them are children.
They have escaped persecution, but they remain in desperate need of protection.
To support UNICEF's work for children affected by this crisis, please click here.
This article was supplied as part of Stuff's partnership with Unicef NZ. Unicef stands up for every child so they can have a childhood. Find out more at unicef.org.nz