A sudden thunderstorm in Halong Bay, Vietnam, overturned a boat, killing at least 35 people and leaving four missing. Survivors describe how the storm capsized the vessel within seconds. The tragedy,

HANOI, Vietnam (AP) — Vietnam braced for Typhoon Wipha on Monday as coastal provinces were placed on emergency alert and airlines canceled flights ahead of the storm’s expected landfall early Tuesday.

Rescue teams on Monday morning recovered the body of a six-year-old boy, one of the last four remaining victims unaccounted for following the tragic capsizing of the Vinh Xanh 58 tourist boat.

The thunderstorm came so suddenly that it overturned the boat within seconds, said two survivors of the shipwreck which killed at least 35 people in Vietnam's top tourist spot of Halong Bay and left another four missing.