Ruapehu volcano (North Island, New Zealand) - Smithsonian / USGS Weekly Volcanic Activity Report for 17 September-23 September 2008 (Continuing Activity)

Sunday morning at 10:47 am local time, a section of Ruapehu volcano's crater walls collapsed under the pressure of the crater lake. The sudden draining of the lake caused a devastating lahar that travelled down from its altitude at 2500 m to sea level. Fortunately, the flash flood of mud drained through a river channel and no people were injured or killed. Authorities closed roads and the nation's main trunk rail track near the southern base of the mountain on New Zealand's North Island. A similar event happened in 1953 killed when a lahar killed 151 people when it washed away a rail bridge, plunging a passenger train into the raging torrent of mud. ... Read all

According to news articles, a "moderate" lahar from Ruapehu's crater lake traveled E down the Whangaehu River valley on 18 March and reached the sea 140 km away after a soft rock-and-ash dam was breached. The section of dam that failed was about 40 m long and 7 m high. There were no reports of injuries or major damage to infrastructure and only some flooding to farmlands at the base of the volcano. ... Read all