In addition to the usual volcanic hazards, the crater lake of Ruapehu ejects frequent lahars.

At 2797 m, Ruapehu is the highest mountain in the North Island. Three summit craters have been active during the last 10,000 years including South Crater which contains the currently active vent. The active vent is filled by Crater Lake; water from this lake is frequently ejected on to the ice and snow during eruptions causing lahars.

Most Recent Eruption

When

25 September 2007

Where

Ruapehu

Effects

This was an explosive eruption, lasting about 7 minutes. During the eruption explosions spread ash, rocks and water across the summit area, producing lahars in two valleys including one in the Whakapapa ski field. In contrast with the previous eruptions in 1996, there was no high ash plume to produce ash fallout over a wide area.