On This Day

Nevado del Ruiz, Nevado del Ruiz eruption, armero tragedy, armero survivors
Associated Press
Two muddy survivors of the eruption of the volcano Nevado del Ruiz carry sticks as they walk
down a dirt road, Nov. 15, 1985, near Armero, Colombia.

On This Day: Mudslide in Colombia Kills 23,000

November 13, 2010 06:00 AM
by findingDulcinea Staff
On Nov. 13, 1985, a massive mudslide devastated entire towns and killed thousands in Colombia following the volcanic eruption of Nevado del Ruiz.

Nevado del Ruiz’s Crushing Lahars

The Nevado del Ruiz is a large, glacier-covered volcano in central Colombia with a “history of generating deadly volcanic mudflows (lahars) from relatively small-volume eruptions,” writes San Diego State University geology professor Vic Camp. A 1595 eruption killed 636 people, while an 1845 eruption killed over 1,000.

Shortly after 3 p.m. on Nov. 13, 1985, there was a violent steam explosion from the volcano. Authorities, believing that the explosion wasn’t serious, directed nearby residents to remain in their homes. At 7 p.m., the Red Cross ordered an evacuation, but it was soon called off because the volcanic activity appeared to be stopping.

At 9:08 p.m., Nevado del Ruiz began erupting molten rock, causing pyroclastic flows to spread across the peak’s ice caps. Unfortunately, a storm above the volcano blocked the eruption from the view of the people below.

The ice caps rapidly melted, swelling the nearby river and spurring catastrophic floods and mudslides. “As these floods of water descended the volcano, they picked up loose debris and soil from the canyon floors and walls, growing both in volume and density, to form hot lahars,” explains the U.S. Geological Survey’s Cascades Volcano Observatory.

The lahars, moving up to 50 kilometers per hour, hit the town of Armero over two hours after the eruption. “In a few short minutes most of the town was swept away or buried in a torrent of mud and boulders, and three quarters of the townspeople perished,” says the Cascades Volcano Observatory.

The flows also devastated the town of Chinchina, tearing down eight bridges and cutting the town off from the major city of Manizales. It also destroyed Chinchina’s coffee crop, leaving thousands without jobs.

All told, the volcano released about 20 million cubic meters of hot ash and rocks. The ensuing volcanic flows killed 23,000 people, injured 4,500 and left 8,000 homeless.

Relief Efforts

The international community rushed to help Colombia face the disaster. The Colombian government suggested that those looking to send aid should send cash rather than relief items that were extremely complicated to transport. Colombia received massive support from international corporations and grassroots organizers alike.

Colombia received strong support from the United States, which donated more than $1 million in the first week after the disaster. Relief was an international endeavor as “at least 25 other nations [were] involved in aid efforts as well,” reported the Christian Science Monitor.

Could It Have Been Prevented?

The Nevado del Ruiz eruption was relatively small, spewing only about 3 percent of what Mount St. Helens did in 1980. However, the amount of debris in the surrounding area and inadequate emergency planning by local authorities made it a major disaster.

T.L. Wright and T.C. Pierson write in the U.S. Geological Survey Circular that the disaster was “a tragic example of the need to understand the entire history of a volcano in assessing hazards.” The area around Nevado Del Ruiz had been wiped out twice in the previous 400 years, but towns were rebuilt and local authorities did not take the threat of mudflows seriously enough.

The volcano had been showing activity for a year before the eruption. International scientists conducted studies of it and created maps of danger areas. A report by the National Bureau of Geology and Mines (INGEOMINAS), released Oct. 7, 1985, found that an eruption would cause “a 100 percent probability of mudflows,” but “government officials dismissed the report as ‘too alarming’ and authorities did not want to evacuate people until they were assured of the necessity,” writes professor Camp.

Related Topic: Omayra Sanchez

During recovery work, rescue workers found a 13-year-old girl, Omayra Sanchez, trapped in a debris-filled pool of mud. They were unable to free her from the debris, and she died on Nov. 16 of exposure. Photographer Frank Fournier’s picture of the girl won the World Press Photo award for 1986.

“When I took the pictures I felt totally powerless in front of this little girl, who was facing death with courage and dignity,” Fournier told the BBC. “She could sense that her life was going.”

Most Recent Beyond The Headlines