What is Lahar? How a Lahar is formed?

A flow of volcanic mud formed by the mixing of water with Volcanic Ash, often taking the destructive power of an avalanche is known as Lahar. The water may be supplied by seasonal rainfall or by the overflow from a Crater-Lake.

Lahars can also be formed when high-volume or long-duration rainfall occurs during or after an eruption. On steep slopes, rainwater can easily erode and transport fine-grained, loose volcanic sediment and form a slurry, especially if vegetation has not had time to grow back on recent volcanic deposits.