flood called a lahar is can happen when a volcano erupts. Water from
a river or lake can mix with a volcano's debris.
A lahar can happen months and years after an eruption. Volcanic eruptions
change how a river or lake changes direction or amount of water it
holds. Water supplies on a hill or mountain can be forced into the
land around it and cause a landslide. Scientists monitor water supplies
around a volcano and watch for changes in the water bodies around
a flood near a volcano scientists go and measure how much more of
the volcanic debris is eroded. That helps them measure and record
how much of the eruption debris was picked up by the river. They compare
the old measurements to the new measurements.
debris that is fresh and loose is dangerous when water is near. The
water can pick up the debris and move it quickly along with it.