There are many potentially dangerous volcanoes in the Taupo Volcanic Zone. The most severe volcanic eruption since the arrival of Europeans is the Tarawera eruption in 1886. A lahar from Mount Ruapehu derailed a train in 1955 killing 151 people. Even a minor eruption at Ruapehu could cause the loss of electricity for Auckland, due to ash on the power lines, and in the Waikato River (stopping the generation of hydroelectric power).