The internal and external activity of the volcano has increased during the past two weeks. Several pulses of tremor were accompanied by ash emissions that produced plumes that rose up to 8200 feet (2.5km) above the crater.
Ash fell in areas west of the volcano including Pereira, Dosquebradas, Santa Rosa, Chinchiná, Villamaría, and Manizales.
Weak incandescence, probably due to hot gasses, has been noted from the Arenas crater at night.
At the moment, it is unclear whether fresh magma has been involved in the recent activity or whether it is phreatic in origin, i.e. caused by overheated water circulating in the volcano’s upper hydrothermal system.