Wipha, the third storm to hit Vietnam this year, is expected to bring torrential rains from tonight until Wednesday, particularly in the northeastern and central regions.

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.

Typhoon Wipha caused severe weather in southern China and Hong Kong, leading to flash floods, landslides, and disrupted transportation. Guangdong and other coastal provinces faced heavy rainfall and wind hazards.

The Guangxi Meteorological Observatory has issued a Level III typhoon alert, the third-highest level in its four-tier emergency response system. Further heavy rain and thunderstorms are forecast on Monday and Tuesday in some cities in the region, including Fangchenggang and Beihai, with strong winds and short-term gales.

Storm Wipha threatens the region with intense rainfall exceeding 600mm and raises the risk of flash floods and landslides.