Updated

The Rohingya refugees have escaped soldiers and gunfire. They have escaped mobs that stormed through their villages, killing and raping and burning. They have fled Myanmar, their homeland, to find shelter in sprawling refugee camps in neighboring Bangladesh.

Now there's a new danger: rain.

The annual monsoon will soon sweep through the immense camps where some 700,000 Rohingya Muslims have lived since last year, when they poured across the border in search of safety. The clusters of bamboo and plastic huts, built along endless waves of steep hills, are now facing a deluge that, in an average year, dumps anywhere from 40 to 60 centimeters (16 to 24 inches) of rain per month.

"I will not be able to light a fire. The wells will flood and I won't be able to get water. The outhouses will be destroyed. The house might also break down," sobbed Rahana Khatun, 45, who fled Myanmar last year with her husband and five children. "What will happen to us then?"

"I have fled my country. I am grateful to Allah for the little I have here in Bangladesh," she said. "But now the rains are coming and I am so worried!"

Government authorities and aid agencies have warned of a catastrophe if there are heavy rains this year. The monsoon usually reaches Bangladesh in April and reaches its peak between June and August, bringing almost daily downpours. Occasional rains have already hit the camps this year, with the full monsoon expected in the coming weeks. Aid agencies are now pre-positioning supplies across the camps, since flooding could easily block paths to food, water and medical care. With most of the area's foliage long gone, stripped away by refugees looking for firewood, little natural protection remains against mudslides.

The early rains have already loosened the dirt on steep hillsides, and tons of earth has shifted in some places. While a handful of people have been relocated, most remain at risk.

"There are no more trees, no more roots, so there could be massive landslides, burying people that live at the bottom of the hills" and carrying away those who live on hilltops, said UNICEF spokesman Benjamin Steinlechner. "So that is the major risk."

An even bigger worry is cyclones forming in the nearby Bay of Bengal.

Cyclones used to regularly kill thousands in Bangladesh, with the storms sweeping through low-lying areas and devastating everything in their path. The country has made remarkable progress against the storms over last few decades, installing networks of warning systems and fortified shelters. But there are no reinforced shelters in the camps.

The Bangladesh Red Crescent Society estimates that at least 100,000 refugees will be exposed to extreme dangers during the monsoon.

"If there is a cyclone, there really is not much more we can do," said Steinlechner. "People will be blown away, houses will be blown away. That's the risk everybody in the camp is facing right now."

"We are reaching out to the people right now to make sure that they know where to go in case they find themselves in an emergency situation," he said.

Construction workers are building 200 new homes in part of the Kutupalong camp. The homes, funded by overseas donors, will have concrete floors, bamboo walls and tarpaulin roofs. Other workers are planting grass and trees around the homes to help prevent erosion and landslides.

But even those homes, some of the best for kilometers (miles) around, won't be able to withstand a major storm.

"It's not enough, not at all," said Dipu Dhali, a construction foreman. "Only 200 families will be relocated here, but what will happen to thousands of other families?"

While some Rohingya refugees have lived in Bangladesh for decades, hundreds of thousands more fled here after Myanmar security forces launched a scorched-earth campaign in late August in response to attacks by a Rohingya insurgent group. Thousands of people are believed to have been killed in the crackdown, which many rights activists believe was a calculated attempt to drive Rohingya from the country.

Rohingya are denied citizenship in overwhelmingly Buddhist Myanmar, where they have long faced persecution. Many in Myanmar see them as illegal migrants from Bangladesh, and deride them as "Bengalis." Most have long lived in poverty in Myanmar's Rakhine state, next to Bangladesh.

In the camps, residents are doing whatever they can to prepare for the rains, using sandbags, ropes and bamboo.

Hazera Begum helped her husband on a recent day to reinforce their home, in the steep hills of the Balukhali camp, with more bamboo and plastic sheeting. They know they can't completely protect themselves, and are simply hoping for the best.

"Rainy days are coming," she said.