ALBERT

Description: The crater of Mount St. Helens is a unique place to study landscape evolution impacted by volcano-ice interactions. Crater Glacier, which started forming after the 1980 eruption, is one of the world’s last expanding glaciers and provides a remarkable opportunity to characterize the expansion of a glacier in an area of significant thermal flux. Although the lava dome is gradually cooling, present thermal and physical interactions with the encircling glacier are considerable. Glacier surface structures caused by these interactions provide insight to the heat distribution of the dome and illustrate the dynamics of such environments. By combining photographic documentation, subglacial cave surveys, and remote sensing we provide a comprehensive overview of landscape evolution in the active Mount St. Helens crater since the 2004-2008 lava dome was emplaced. Our results show that the glacier toe advanced by several hundred meters, and constant rockfall from the crater walls transformed the glacier into one that is debris-covered, including the development of supraglacial ponds. The shift of the glacier-dome interface towards higher elevations at the dome has led to extensive subglacial cave system formation, particularly around the 2004-2008 dome. Based on the recent evolution of Crater Glacier and our time series analysis of cave surveys and remote sensing data, we speculate about the future development of this volcanic landscape. Investigating volcano-ice interactions may be an important monitoring tool as these interactions provide insight to the evolution of a volcanic edifice and may be an indicator for renewed volcanic activity.