Glacial Lake Outburst Floods: Geomorphological Agents and Hazardous Phenomena

Abstract

Glacial lake outburst floods (GLOFs) are sudden pulses of meltwater and sediment from lakes dammed by moraines, glacier ice, or located in bedrock overdeepenings. GLOFs had some of the highest flood volumes, discharges, sediment transport rates, and runouts from freshwater floods in Earth's history. GLOFs can cause substantial erosion, aggradation, and avulsion in river channels, accentuating their role in landscape development in glaciated regions. Their role as a natural hazard has become increasingly important in a changing cryosphere with rising exposure to population and infrastructure, retreating glaciers, and growing glacial lake volumes. In this contribution, we characterize geomorphological preconditions for, and consequences from, glacial lake outburst floods, including GLOF triggers and their hydro-dynamical properties. We review the global distribution of reported GLOFs, discuss their occurrence under ongoing atmospheric warming in past decades, and show recent progress in modeling and GLOF processes and impacts.