The volcano continues to pose a serious threat to nearby towns and villages. Of the threats, the one with the most potential for danger is that of small-volume eruptions, which can destabilize glaciers and trigger lahars. Although much of the volcano's glacier mass has retreated, a significant volume of ice still sits atop Nevado del Ruiz and other volcanoes in the Ruiz-Tolima massif. Melting just 10 percent of the ice would produce lahars with a volume of up to - similar to the lahar that destroyed Armero in 1985. In just hours, these lahars can travel up to along river valleys.