Conference Goals & Themes
The century following the start of the “Spokane Flood” debate has seen tremendous growth in the understanding of the significant role outburst floods have played in shaping the surfaces of Earth and Mars. Study of the geomorphology and hydrology of outburst floods has, in turn, generated hypotheses regarding the role such floods play in driving climate change and a greater recognition of the geo-hazards associated with outburst flooding. The objective of this Penrose Conference is to bring together a diverse community of scholars to discuss the current state of knowledge and chart the future of outburst flood science. The timing of the proposed conference in 2023 is also historically significant, as it marks the centennial anniversary of J Harlen Bretz’s first publication on the Channeled Scabland.
The conference will address a wide variety of topics pertaining to outburst floods, bringing together scientists from a range of disciplines and interests to discover and define productive research directions and potential collaborations.
The conference will be organized around four focused but overlapping themes:
1) The Channeled Scabland and the Missoula Floods
The Missoula Floods and the Channeled Scabland are a “Megaflood testing ground” for studies applicable throughout the solar system. It is here where Bretz’s controversial and outrageous hypothesis for a flood origin of the Channeled Scabland brought huge ice-age outburst floods into the realm of modern Earth science. The Channeled Scabland continues to inspire geological analysis and modeling approaches, and this spectacular geographic area has long attracted attention, culturally and scientifically. This thematic session will explore the state of knowledge of the Channeled Scabland landscape and the Missoula floods, as well as the scientific controversies that have persisted for the past century and continue today.
2) Outburst Floods—A Universal Process
A wide range of geological processes lead to impoundment of water bodies that can then rapidly drain to cause large floods, ranging from tectonics to meteor impacts. Floods from ice-dammed, moraine-dammed, and landslide-dammed lakes can cause human catastrophes. Floods from constructed dams have also profoundly affected landscapes and people. Spectacular flood-carved landscapes on other planets, particularly Mars, owe to huge outburst floods. The diversity of settings, processes, and hazards results in a wide range of backgrounds, disciplines, and geographies represented by outburst flood researchers, including engineers, geomechanicists, glaciologists, volcanologists, geologists, geographers, hydrologists, and planetary scientists. This thematic session aims to search for commonalities and distinctions among outburst flood generation mechanisms and geomorphic consequences (across landscapes and planets), thereby enriching the perspective for the outburst flood research community.
3) Mechanistic Understanding of Outburst Flood Processes—Flow, Erosion, and Deposition
Outburst floods produce spectacular features—huge cataract complexes, eroded rock basins streamlined landforms, and immense stratified deposits. Given the lack of in situ observations of ice-age and planetary megaflood processes, various methods have been used to address historical questions regarding flood magnitude, the number of floods, or the shear stresses generated by flooding, including empirical, stratigraphic, mechanistic, modeling, and physical experimentation. The development, refinement, and testing of mechanistic models has been key to advancing the overall understanding of how outburst floods drive the evolution of planetary surfaces. The objective of this thematic session is to generate discussion that charts a path for novel approaches for mechanistic understanding of the energetic and dynamic flows that produce outburst flood landforms.
4) Broader Implications of Outburst Floods—Cultural Consequences and Hazards, Ocean Circulation and Climatic Systems, Ecosystems, and Landscape Evolution
The hazards and impacts from outburst floods are immense, global, and diverse, begging several overarching questions. Are there specific geologic and climatologic settings that can condition such hazards and preserve evidence of paleo-outburst floods? What are persistent cultural consequences of outburst floods, such as the landslide dam flood that has been attributed to marking the beginning of the Xia dynasty and onset of the Chinese Bronze Age? Can the formation of glacier dams and erosion by outburst floods influence long-term exhumation and geodynamics in uplifting mountains? More broadly, how do outburst floods affect landscapes on geologic time scales? Aside from landscape impacts, it is also important to consider climate impacts—can large outburst floods trigger global or regional climate changes? This fourth thematic session will address these broad interdisciplinary questions, searching for directions of productive inquiry relevant to the culturally and scientifically important aspects of outburst floods.