At least 37 people have been confirmed dead and several more remain missing after a tourist boat capsized in Vietnam’s Ha Long Bay during a sudden and violent storm on Saturday afternoon, officials said.

The vessel, named Wonder Seas, was carrying 53 passengers—primarily Vietnamese families from Hanoi—when it was caught in a powerful storm that brought torrential rain, hail, thunder, and lightning, according to Vietnam’s Border Guards and navy.

An eyewitness told AFP that the sky darkened rapidly around 2:00 p.m. local time and described “hailstones as big as toes” pounding the boat before it overturned in the UNESCO World Heritage Site located in Quang Ninh province.

Despite extreme weather conditions hindering rescue efforts, 11 people have been pulled from the water alive. Among the survivors is a 10-year-old boy who found shelter in an air pocket beneath the upturned hull.

“I took a deep breath… dived, then swam up. I even shouted for help, then I was pulled up by a boat,” the boy, who had been traveling with his parents, told the state-run outlet VietnamNet.

According to VNExpress, at least eight of the confirmed fatalities were children. As of Saturday night, emergency crews continue search and rescue operations in the hope of finding more survivors.

Prime Minister Pham Minh Chinh extended his condolences to the victims’ families and has ordered an urgent investigation into the incident. In a statement, the government vowed to “strictly handle violations” and determine the exact cause of the disaster.

Ha Long Bay, renowned for its striking limestone karsts and emerald waters, is one of Vietnam’s top tourist destinations, drawing more than four million visitors annually before the pandemic.

The tragedy has sparked questions about safety protocols and storm preparedness in the bay, especially during peak tourist seasons.