The volcano continues to pose a serious threat to nearby towns and villages. The most likely hazard is small-volume eruptions, which might destabilize glaciers and trigger lahars. Despite the significant retrenchment of the volcano's glaciers, the volume of ice atop Nevado del Ruiz and other volcanoes in the Ruiz–Tolima massif remains large. Melting merely 10% of the ice would produce mudflows with a volume of up to —similar to the mudflow that destroyed Armero in 1985. Such lahars can travel up to along river valleys in a matter of few hours. Estimates show that up to 500,000 people living in the Combeima, Chinchiná, Coello-Toche, and Guali valleys are in danger, and 100,000 of these are considered to be at high risk. Lahars pose a threat to nearby towns of Honda, Mariquita, Ambalema, Chinchiná, Herveo, Villa Hermosa, Salgar and La Dorada. Although small eruptions are more likely, the two million-year eruptive history of the Ruiz–Tolima massif includes numerous large eruptions, indicating that the threat of a large eruption cannot be ignored.