(CNN)The first signs of incoming monsoon rains have been felt in Rohingya refugee camps in southeastern Bangladesh.
'Pre-monsoon' rains begin in Bangladesh, highlighting plight of Rohingya refugees
Following showers Wednesday, the camps were subjected to a heavy downpour Thursday, according to reports from aid group Save the Children.
The monsoon season, which begins in earnest in about a month, will potentially imperil hundreds of thousands of Rohingya refugees huddled in low-lying makeshift camps along the country's eastern border.
Heavy rain fell for over an hour, Daphnee Cook, Save the Children's media and communications manager, reported from Cox's Bazar. Further rain showers are forecast over the next few days, she said, "threatening an already vulnerable population."
More than 670,000 Rohingya refugees, fleeing violence in Myanmar's western Rakhine state, are massed in camps along the border.
Just an hour of heavy rain had a severe effect in the camps, Cook said, with flooding rapidly occurring and mud forming.
"As we feared, this first deluge is already wreaking havoc in the camps, with a number of low-lying areas flooded and access made much more difficult. It was alarming how quickly dirt turned into mud and puddles the size of wading pools formed," she added.
Even as the camps fill with water and the health and safety situations become tenuous, the recent rains are only a foreshadowing of things to come.
"Bangladesh, and the region around Cox's Bazar should not expect much in the way of monsoonal rains for another month yet," said CNN meteorologist Jenn Varian. The monsoon season typically lasts until around October.
Hundreds of thousands of Rohingya Muslim refugees have fled Buddhist-majority Myanmar into neighboring Bangladesh since August 2017, bringing with them stories of murder, rape and the destruction of villages at the hands of the military.
The UN and the US say they believe the violence against the Rohingya, which are members of a minority ethnic group, constitutes ethnic cleansing. Myanmar denies most of the charges, saying its military has only targeted suspected terrorists that killed 12 security officials in late August.
"These rains signal even harder times ahead for Rohingya families who fled brutal violence in Myanmar," Cook said.
"In the coming months we're going to see regular heavy rains that are guaranteed to bring even further hardship -- destroying people's shelters, flooding roads and making access to the camps extremely difficult."
She added that the region is also "at the beginning of the cyclone season. If a big storm hits the camps, it would be nothing short of disastrous."
CNN's Varian says that the seasonal storms, which are more prominent between April and November, would have the "potential to damage these camps fairly severely."
Hillsides around the camps have been denuded of trees, which has left the underlying soil vulnerable to landslides. The camps' sewage and drainage systems, which are rudimentary, are also prone to failure, meaning that the spread of water-borne diseases like cholera is likely.
"With the flooding and accumulation of stagnant water, water- and mosquito-borne diseases are all the more likely to spread because of the refugees' severely overcrowded living conditions and very poor sanitation," said medical aid group Medicines Sans Frontiers (MSF) emergency coordinator in Cox's Bazar, Francesco Segoni.
Refugees are "facing grim conditions in overcrowded refugee camps where they rely on food rations to survive, but now they have to worry about dangerous storms, heavy rains and the risk of flooding and landslides, as well as an increased likelihood of outbreaks of disease," Cook said.
"This weather is particularly concerning for children, who risk becoming separated from their families and caregivers, as well as developing skin diseases due to increased humidity. They also risk losing access to vital services like health clinics, nutrition centers and child-friendly spaces, which provide them with a sense of calm and happiness in the camps."
Aid groups, the Bangladeshi government and non-governmental agencies have been preparing for the annual deluge for months, but the situation is made almost impossible to manage given the scale of the refugee crisis.
The UN High Commissioner for Refugees (UNHCR) told CNN that a survey commissioned by the agency has estimated more than 100,000 people in the main settlement, Kutupalong-Balukhali, were at high risk of floods and landslides and should ideally be relocated.
Earlier in the year the government allocated 500 acres of new land to house relocated refugees, "which is massively welcomed, but we still believe the sites are not large enough to move everyone who needs to be moved," Caroline Gluck, UNHCR Senior Public Information Officer, said last month.
UNHCR and its partners have also been delivering tens of thousands of shelter kits, to ensure that families have "sturdier, more robust and waterproof shelters."
Larger infrastructure projects, such as the construction of steps, pathways and bridges to allow camp residents access to services, have been undertaken.
MSF recently finished construction of a medical facility in the vicinity, which can handle outbreaks of cholera and hepatitis E, which are common during the rainy season, but the group warned things will be "extremely challenging."
According to Bangladeshi media, earlier this week Myanmar's Social Welfare Minister Win Myat Aye told reporters in Yangon that conditions in the camp are "very poor," and suggested that repatriation of the Rohingya refugees back to Myanmar needed to get underway as the monsoon threat loomed.
"Seeing is believing and we saw all the people in the camps are in very poor condition," the minister said following a two-day visit to camps in Cox's Bazar.
"Our main thing is to start the repatriation process as soon as possible because the monsoon is very near and we are very worried for those who fled to Bangladesh," he said.
In a statement on Saturday, Myanmar said it had repatriated the first Rohingya family from refugees who have fled to Bangladesh. However, the UNHCR, said in a statement Sunday that it had no direct knowledge of the case and was not consulted or involved in this reported return.
Bangladesh's Refugee Relief and Repatriation Commissioner, Abul Kalam, also disputed the claim.