Keith N Musselman, Institute for Arctic and Alpine Research, Boulder, CO, United States; University of Colorado, Boulder, Boulder, CO, United States, Henry T Berglund, GPS Solutions Inc., Boulder, CO, United States, Kehan Yang, University of Colorado, Boulder, Department of Geography, Institute of Arctic and Alpine Research, Boulder, United States and Noah P Molotch, University of Colorado at Boulder, Geography / INSTAAR, Boulder, CO, United States