This paper discusses debris and mud flash flood, which is a widespread phenomenon with different levels of damaging effects and repetition in the mountainous areas of Vietnam. There are some sites where the flash flood with severe debris components has recurred many times and it has always caused heavy loss of human and materials, such as Lay Nua Commune, the Former Muong Lay District, Dien Bien Province. During the 1990s, this kind of severe hazard is recorded to occur every two years in the town of Former Muong Lay District. This leads to the government’s decision to relocate the town to another place. Some characteristics of physiographical conditions such as climate, relief, litho...
