Nevado del Ruiz

Nevado del Ruiz is a glacier-capped stratovolcano in the Andes of central Colombia, reaching about 5,321 meters, the northernmost of the country's major active volcanoes and part of the same Andean subduction-driven volcanic arc as Cotopaxi and Villarrica, both documented elsewhere in this section. Built from andesitic and dacitic material, the volcano is infamous for the catastrophic eruption of November 13, 1985, a relatively modest explosive event by volcanic standards that nonetheless melted a significant portion of its summit ice cap, generating massive lahars that raced down river valleys and buried the town of Armero, killing an estimated 23,000 people in one of the deadliest volcanic disasters of the 20th century. The disaster is widely cited in volcanology and disaster-management literature as a preventable tragedy, since scientists had warned of the specific lahar hazard in the weeks beforehand, but evacuation orders were delayed and poorly communicated. The volcano has remained intermittently active since, with renewed unrest and minor eruptive activity recorded in the following decades, and its ice cap, like those of other tropical Andean peaks, has continued to retreat. This entity documents Nevado del Ruiz specifically as a geological formation, an ice-capped Colombian stratovolcano whose 1985 lahar disaster killed an estimated 23,000 people in Armero.