Spectacular eruptions occurred during 1995 and 1996. Ruapehu had been showing signs of increased activity since late November 1994, with elevated Crater Lake temperatures and a series of eruptions that increased in intensity over about nine months. Several lahars were observed, both in the Whangaehu River and other areas of the mountain, between 18 September and 25 September 1995, indicating Crater Lake was being emptied by the eruptions.