Figure 12. Conceptual model for the various types of dams and edifices that may have formed in western Grand Canyon. The incorporation of volcanic debris into dams would add instabilities that would lead to more rapid destruction of that part of the dam but not necessarily cause catastrophic failure before overtopping. The presence of lava tubes would allow for infiltration of the edifices and cause rapid destruction. In this depiction, the stability of dams is shown by the degree to which they are preserved.