The volcano erupted at 5:40 p.m. Saturday, spewing a plume of ash and vapor more than six miles into the Andean skies.
The mountain awakened from 25 years of slumber in September 2010 and has produced several troublesome eruptions since that time.
Officials distributed about 30,000 face masks to residents around the volcano to be used if a more violent eruption spewed dangerous amounts of ash into the sky.
Nevado del Ruiz’s greatest threat to the area is from slides of volcanic debris, or lahars, which cascaded down the mountain with deadly force in 1985.
One lahar wiped out the town of Armero, killing everyone there.
Photo: Colombian Institute of Geology and Mining