From Glossary of Meteorology


A dense, highly viscous flowing mass of predominantly fine-grained earthy material, with water content approximately 20% by weight (or approximately 40% by volume).

Their high density and viscosity allow mudflows to travel at speeds of more than 10 m s-1 in mountain canyons, and to carry very large boulders on low gradients.

Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.