on Mar 19th, 2007
I didn’t know what a lahar was until I came to New Zealand, but in the last couple of months I’ve been hearing a lot about the Mt. Ruapehu lahar. In the case of Mt. Ruapehu, part of a lake wall was formed during a recent (12 years ago) eruption. The wall had been stable enough to allow a lot a water to accumulate, but geologists knew it was going to burst sooner or later.
Now it has. The scientists’ predictions were for the Feb-Mar time frame, so they get full points for accuracy (unlike their meteorological brothers). No one was hurt, and the monitoring equipment installed to deliver warnings of the impending breach apparently worked. Aside from being an interesting natural phenomenon, the Mt. Ruapehu lahar got/gets a lot of attention because it caused one of New Zealand’s world disasters. The 1953 Tangiwai disaster left 151 people dead when the lahar damaged a railway bridge, resulting in an express train plummeting to the river below. Today’s lahar caused only some flooding and a lot of media coverage.