At around 4 p.m. on Monday, some families in Dong Tien Ward in the northern province of Hoa Binh, two hours west of Hanoi, heard and saw several cracks appear on the ground, and alerted the authorities.

Hundreds of police and army personnel were rushed to the site and an emergency evacuation of five most vulnerable families was carried out.

Around 7 p.m. the same day, the five houses were half-swallowed by the river.

Officials have blocked off the eroded area and urged residents of 25 other houses to move to safety immediately, a representative of Hoa Binh’s Steering Committee on Natural Disaster Prevention, Search and Rescue said.

Nguyen Thanh Huy, a local official, said the authorities have warned of potential erosion since last year because of landslides.

While some residents blamed it on the Hoa Binh hydropower dam, the largest in Southeast Asia, closing its flood discharge gates, causing water levels on the Da River to recede rapidly, officials have said that it is a false assumption.

Nguyen Hong Son, deputy head of the central steering committee for natural disaster prevention, said at a news conference that the recent heavy rains in the northern provinces were responsible for the riverside erosion, Vietnam News Agency reported.

Land erosion has become a frequent occurrence in many coastal and riverine provinces in Vietnam over the last decade. Scores of houses have been lost.

According to Vietnam's agriculture ministry, the Mekong Delta, the country's fruit and rice basket, loses 500 hectares of land to sea and river erosion every year. Hydroelectric dams in the upstream Mekong and climate change have been blamed as the main culprits.

By Gia Chinh - - July 31, 2018