In 1985, the Nevado del Ruiz volcano in Colombia erupted after lying dormant for 69 years. The eruption sent enormous lahars down the volcano and killed 20,000 of the 29,000 residents in the town of Armero. 3,000 other deaths were recorded in other neighbouring towns. The Armero tragedy was Colombia’s deadliest natural disaster and the fourth-deadliest volcanic event recorded since 1500.
The market town of San Lorenzo was founded by Spanish settlers in the 16th century and soon became the centre of the country’s cotton industry. In 1930, the name was changed to Armero after José León Armero, a national martyr. It was located 169 kilometers (105 mi) from Colombia’s capital of Bogotá. The rich agricultural land surrounding the town can be attributed to the Nevado del Ruiz volcano located 48 kilometers (30 mi) away. It would also eventually lead to its destruction.
Previous eruptions of Nevado del Ruiz in 1595 and 1845 caused damage to the town however loss of life wasn’t huge and each time, the town was rebuilt and improved. The last eruption before the Armero tragedy was in 1916 when damage was minimal. The volcano fell silent for sixty nine years.
In late 1984, tremors were felt near the volcano and geologists predicted an eruption would happen soon. With glacial ice built up over the winter, the possibility of lahars was high and the geologists predicted any magma coming through the summit could have devastating effects. The seismic activity continued until September 1985 when phreatic eruptions blasted steam into the air. Earthquakes shook the surrounding area and experts urged local officials to evacuate.
A hazard map was created for the area around Nevado del Ruiz by October but was not widely distributed to the population. It was poorly designed and met with strong opposition from economic interests in the region.
On 13 November 13 1985, black ash began spewing from the volcano. Colombia’s geological organisation, the Instituto Nacional de Investigaciones Geológico-Mineras (INGEOMINAS), ordered an immediate evacuation. At 5pm, the ash stopped falling and locals were told to stay inside by officials. An emergency meeting was concluded at 7pm, at which point the regional Red Cross began gave the instruction that Armero, Mariquita, and Honda should be evacuated immediately. A storm raging in the area meant evacuation communications were not heard in Armero. The population there was unaware of the continued activity at Nevado del Ruiz and very likely confused the noise of the eruption with that of the storm. The confusion around the evacuation order meant many people stayed indoors as they had been instructed previously.
At 9:09pm, Nevado del Ruiz erupted. Debris was thrown more than 30 kilometres (20 mi) into the atmosphere, filling the sky with sulphur. The eruption produced pyroclastic flows that melted summit glaciers and snow, creating four thick lahars. They flowed down the volcano’s sides at 60 kilometres per hour (40 mph) destroying vegetation and dislodging rocks. They entered river valleys at the bottom of the volcano where they continued to grow in size.
Residents in Armero had remained indoors, still unaware of the eruption. The electricity had turned off during the night and at 11:30pm, a stream of water entered the town. Locals believed it to be a flood and as they investigated, the first lahar hit. Armero was virtually destroyed as three lahars in total hit the town. 85% of it was completely covered in mud and debris. Thousands of people were killed instantly. A final lahar hit the town of Chinchina and killed 1,800 people there. 13 towns and villages in total were destroyed.
In the aftermath of the tragedy, Omayra Sánchez became the enduring image of the relief operation. The 13-year-old girl had become trapped up to her neck in water, pinned down by the debris of her house. Journalists and relief workers tried to comfort her as attempts were made to rescue her. After some of the water was drained, it was discovered that her legs were bent under concrete and it would be impossible to release her without a double amputation. Doctors lacked the surgical equipment for such a procedure and they agonisingly decided that the most humane thing to do was to let her die. Omayra Sánchez died at 10:05am on November 16, 3 days after the lahar hit Armero.
Controversy followed the disaster. Even though the Colombian government had been warned of the impending dangers, they decided not to evacuate the towns near the volcano and as a result, 23,000 lives were lost. Geologists had insisted tragedy was imminent however the residents were not informed. As a direct result of the disaster, the Colombian government created an office to promote awareness of natural disasters – Oficina Nacional para la Atención de Desastres (National Office for Disaster Preparedness), now known as the Dirección de Prevención y Atención de Desastres (Directorate for Disaster Prevention and Preparedness). Armero was never rebuilt and the survivors were relocated to the towns of Guayabal and Lérida.
Elsewhere, the lessons from the Armero tragedy have inspired a lahar warning system for Mt. Rainier in Washington State, USA. The warnings given before the eruption of the Soufrière Hills in 1999 saved many lives, even though Plymouth, the capital of Montserrat, was destroyed.