Glacial retreat in recent decades has exposed unstable slopes and allowed deep water to extend beneath some of those slopes. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. The resulting tsunami reached elevations as high as 193 m, one of the highest tsunami runups ever documented worldwide. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. The event was detected within hours through automated seismological techniques, which also estimated the mass and direction of the slide - all of which were later confirmed by remote sensing. Our field observations provide a benchmark for modeling landslide and tsunami hazards. Inverse and forward modeling can provide the framework of a detailed understanding of the geologic and hazards implications of similar events. Our results call attention to an indirect effect of climate change that is increasing the frequency and magnitude of natural hazards near glaciated mountains.

As climate change drives the world toward a warmer and more unpredictable future, it presents significant challenges for geographers and geomorphologists: how will Earth's surface evolve? While landscapes may never be in perfect equilibrium with their formative processes, there is no doubt that climate change—and the shifting frequencies, magnitudes, and intensities of geomorphic events—is creating widespread disequilibrium. Rapid, real-time landscape transformation is evident in phenomena such as sea level rise, glacial retreat, mega-wildfires, and permafrost melting. Fundamental questions for current and future generations of earth scientists include: Can we predict the trajectory of these landscapes? How long will the transformations take, and what will the resulting landscapes look like? What will the consequences be for humans and other species, and is our science adequate for the task of prediction?Southeast Alaska, a vast and dramatic region, serves as a natural laboratory for exploring these questions. Subject to the aforementioned climate drivers, as well as the world’s highest rates of isostatic rebound, frequent tectonic uplift, and exceptional precipitation intensities, the landscape is transforming before our eyes, acting as a global bellwether for geographic change.Drawing on examples from this dynamic environment, this presentation will explore the prospects for predicting geomorphic change, anticipating its consequences, and extracting lessons applicable to other regions. Specifically we will identify regions where rapidly melting and thinning glaciers are likely to cause dramatic landscape changes, including drainage captures, fluvial redirection, landslide acceleration, and delta abandonment. We will elaborate on the consequences of these plausible changes to ecosystems, human infrastructure, and natural hazards, and suggest the roles that models and scientists might play in anticipating these changes and communicating them to broader audiences.