Reconstructing glacial outburst floods (jökulhlaups) from geomorphology: challenges, solutions, and an enhanced interpretive framework
journal contributionposted on 12.11.2021, 11:14 by Greta Wells, Andrew Dugmore, Timothy Beach, Edwin BaynesEdwin Baynes, Þorsteinn Sæmundsson, Sheryl Luzzadder-Beach
Glacial outburst floods (jökulhlaups) have been significant drivers of landscape change across Earth throughout the Quaternary and are a contemporary hazard in Arctic and alpine regions worldwide. Geomorphologic evidence is a foundation for reconstructing past and contemporary flood events and using additional analytical methods such as geochronology and paleohydraulics. Yet, accurate interpretation of jökulhlaup landforms and depositional sequences poses a persistent challenge due to complex controls on flood hydraulics and landscape evolution. Researchers have developed numerous strategies to reduce or resolve these challenges, but a comprehensive, globally applicable model to interpret flood evidence outside of sedimentary environments is lacking. This article synthesizes existing case studies to describe jökulhlaup geomorphologic interpretive challenges, discuss strategies to resolve them, and present a conceptual model of flood landform assemblages to illustrate hydraulic and environmental controls on resultant geomorphologic impacts. This enhanced interpretive framework aids researchers in identifying, interpreting, and testing geomorphologic evidence to reconstruct past jökulhlaups and predict future flood impacts as robustly as possible at a global, landscape-wide scale. Understanding jökulhlaup geomorphology yields insight into glacial lake and ice margin dynamics, the role of extreme events in landscape evolution, and interactions between climate, ice sheets, and hydrology. Moreover, it is increasingly important as glacial outburst floods may become more frequent due to climate-driven ice retreat, advancing predictive capacities to mitigate societal risk downstream.
The ideas in this manuscript were developed during field work funded by grants to GHW from the Leifur Eiríksson Foundation Fellowship, American-Scandinavian Foundation Fellowship, American Association of Geographers Dissertation Research Grant, Explorers Club Exploration Fund Grant, Geological Society of America Graduate Student Research Grant, and University of Texas-Austin Global Research Fellowship. GHW completed this manuscript while on a Fulbright Iceland-NSF Arctic Research Grant, a University of Texas-Austin Graduate Continuing Fellowship, and a University of Texas-Austin graduate research assistant position.
- Social Sciences and Humanities
- Geography and Environment