Page "Lahar" Paragraph 3

Lahars vary in size and speed.

Small lahars less than a few meters wide and several centimeters deep may flow a few meters per second.

Large lahars hundreds of meters wide and tens of meters deep can flow several tens of meters per second: much too fast for people to outrun.

With the potential to flow at speeds up to, and distances of more than, a lahar can cause catastrophic destruction in its path.

Lahars from the 1985 Nevado del Ruiz eruption in Colombia caused the Armero tragedy, which killed an estimated 23, 000 people, when the city of Armero was buried under of mud and debris.

A lahar caused New Zealand's Tangiwai disaster, where 151 people died after a Christmas Eve express train fell into the Whangaehu River.

Lahars have been responsible for 17 % of volcano-related deaths between 1783 and 1997.

A lahar can cause fatalities years after its precipitating eruption.

For example, the Cabalantian tragedy occurred four years subsequent to the 1991 eruption of Mount Pinatubo.