20. An Easily Avoidable Disaster That Wasn’t
The Nevado del Ruiz Eruption killed about 25,000 people. That made it the 20th century’s second deadliest volcanic eruption, exceeded only by that of Mount Pelee. Sadly, the massive casualties could have easily been avoided: volcanologists had detected clear signs of an impending eruption two months before it happened, and warned the authorities of the impending disaster.
The location of Nevado del Ruiz by a river valley made the risk of lahars obvious. That, coupled with the glaciers atop the volcano which would supercharge such lahars in case of an eruption, made the dangers to Armero and its surroundings even clearer. Volcanologists and seismologists from multiple organizations warned the Colombian government to evacuate Armero, but were ignored.
Read More: 10 Worst Volcanic Eruptions of the 20th Century.