Nevado del Ruiz
Nevado del Ruiz, volcano, 17,457 ft (5,321 m) high, in the Cordillera Central of the N Andes, E Colombia, on the Caldas-Tolima dept. border. A broad, glacier-covered stratovolcano, it can produce explosive eruptions with pyroclastic flows, and the melting of glaciers by those hot gases has resulted in devastating lahars (fast-moving mud and debris flows) during its eruptions, most recently in Nov., 1985, when a lahar buried or washed away Armero, a town 46 mi (74 km) away. The 1985 eruption, in which some 23,000 died, was one of the deadliest volcanic disasters of the 20th cent.