e volcano. Future eruptions may occur without warning." However the level has remained at 1. It has been at this level since 1997.
2011 warnings
On 5 April 2011 Geonet changed Mount Ruapehu's Volcanic Aviation Colour Code from Green to Yellow (elevated unrest above the known background). Ruapehu's Volcanic Alert Level remained at level 1 (signs of volcanic unrest). The Volcanic Aviation Colour Code was changed because a sustained period of high water temperatures in the Crater Lake (approximately 38 - 39 �C) was observed and because changes were observed in volcanic gas output, seismic activity and Crater Lake water chemistry
