Tropical cyclone Mocha intensified to become “very dangerous” on Friday, the World Meteorological Organization (WMO) said, warning of violent winds, floods and possible landslides in Bangladesh that could hit the world’s biggest refugee camp.

The WMO’s Clare Nullis told a Geneva press briefing that a storm surge of 2-2.5 meters over the weekend was likely to inundate low-lying areas of North Myanmar as well as parts of Bangladesh where flash floods and landslides were also possible.

“It’s a very dangerous cyclone and…it’s associated with violent winds,” she said. “There will be major impacts both ahead and after landfall for potentially hundreds of thousands of the world’s most vulnerable people,” she added.

The cyclone is currently set to make landfall in Bangladesh on Sunday. While a direct hit is not expected, the storm’s path is set to affect Bangladesh’s southeastern border district of Cox’s Bazar where a million Rohingya refugees live.

Most of them fled there after a military-led crackdown in neighbouring Myanmar in 2017.

U.N. refugee agency spokesperson Olga Sarrado said preparations were underway for a partial evacuation of the camp, if needed. The agency was also preparing tens of thousands of hot meals and jerrycans, she said.

The World Health Organization said it was pre-positioning some 33 mobile medical teams, 40 ambulances as well as emergency surgery and cholera kits for the camp.

In Myanmar, the WHO was pre-positioning 500,000 water purification tablets among other supplies which amount to the entire monsoon season stocks.

“If this turns into the level of cyclone we fear, we really need to be ready,” the WHO’s Margaret Harris told the briefing.