HANOI - Floods and landslides caused by torrential rains have killed 26 people and left 15 missing in Vietnam's mountainous north, authorities said Monday. Since the start of August, flash floods have caused widespread destruction in the provinces of Dien Bien, Yen Bai, Son La, Cao Bang and Lai Chau, the Hanoi-based disaster control office said in a statement. "Twenty-six people are dead, 15 missing and 27 others were injured," it said. According to witnesses in Yen Bai province, floods tore through villages on Thursday night, carrying with them large boulders from the mountains.