HANOI, July 20 (Xinhua) -- A flash flood triggered by Typhoon Son Tinh killed two people and left another two missing in Vietnam's central Thanh Hoa province early Friday, the provincial authorities said.

The four belonged to the same family in Lang Chanh district. The bodies of a 75-year-old woman and a 40-year-old man have been found, and the other two, including a 28-year-old woman and a four-year-old girl, have gone missing, the authorities said on Friday.

Besides the victims' house, two other houses were swept away by the flood.

Over the past two days, Typhoon Son Tinh, which rapidly weakened into a tropical depression, has brought torrential rain and high levels of waters in rivers and reservoir lakes to Vietnam's central and northern regions, especially Thanh Hoa and its neighboring Nghe An province.

In Nghe An, the typhoon and the subsequent tropical depression have inundated some 21,000 hectares of rice and others crops and over 922 hectares of aquaculture ponds, damaged 15.8 km of roads, and brought down 31 electricity poles, said the provincial authorities.

According to Vietnam's National Center for Hydro-meteorological Forecasting, heavy rain may last for days in the northern and central provinces, and more flash floods and landslides are likely to hit Thanh Hoa and Nghe An.

In the first half of this year, natural disasters, mainly floods and landslides, killed or left missing 33 people and injured 47 others, destroyed or damaged 15,000 houses, and damaged nearly 11,000 hectares of rice and other crops in Vietnam, causing property losses of over 808 billion Vietnamese dong (35.6 million U.S. dollars), according to the General Statistics Office.