Nevado del Ruiz
A lack of preparation contributed to the high death toll. Armero had been built directly on old mudflows and authorities ignored a hazard-zone map which showed the potential damage to the town if lahars were to avalanche down the mountain. Habitants were also told to stay inside and avoid the falling ash, not thinking the mudflows would bury them. Dr. Stanley Williams of Louisiana University said that following the eruption, "With the possible exception of Mount St. Helens in the state of Washington, no other volcano in the Western Hemisphere is being watched so elaborately."