noncohesive lahar

^{ALASKA VOLCANO OBSERVATORY GLOSSARY}

A type of volcanic debris flow that contains less than 3-5 percent clay in the deposit matrix. Such lahars form when meltwater produced by the interaction of pyroclastic flows and snow or ice picks up locally available sediment on the flanks of a volcano, or in stream channels developed on the volcano. Noncohesive lahars usually evolve downstream into watery sediment-laden flows called hyperconcentrated flows, or floods.