1. In some cases lahars travel large distances and form thick deposits up to tens of metres deep.
2. In 1953 a lahar swept away a railway bridge at Tangiwai at the base of the mountain and 151 people were killed when an Auckland-to-Wellington train plunged into a river.
3. In March 2007 a mudflow, or "lahar" flowed down the side of the mountain after the crater lake overflowed, and large eruptions in 1995 and 1996 blanketed the surrounding area in ash.
4. lahar—an avalanche of volcanic ash and rock mixed with water—50 kilometers (30 miles) down the west side of the volcano summit.
5. The dried, hardened remains of the lahar persist today, a streak of barren rock on a landscape that is otherwise richly vegetated.
6. Another lahar in 1953 caused New Zealand's worst rail disaster, killing 151 people.
7. Thousands of hectares of snake fruit plantations in Yogyakarta may turn arid after six irrigation dams were damaged by lahar following recent volcanic eruptions on Mount Merapi.
8. Concern has responded to several disasters over the years, including the 1991 eruption of Mt. Pinatubo and the subsequent lahar flows, which lasted for more than five years.
9. The problem is also compounded by the still present threat of lahar. If the dams are repaired, they could be hit by fresh lahar, he added.