My 4-year-old niece has developed a healthy interest in volcanoes. She asked about where lava comes from and what happens to the trees and houses that are in the lava’s path. She also asked, “What happens to the lava if it is snowing”. This question made me think of lahars, which typically form when lava melts enough snow and ice to create a muddy slurry. One such lahar, which originated on Mt. Ruapehu (pictured above), took out a train bridge much further down stream. A locomotive and first six cars derailed, killing 151 people, in 1953 and is known as the Tangiwai disaster. I still get the chills whenever I travel past that site.