Numerical modeling of ice detachment tipping processes: insights from the Sedongpu Glacier, southeastern Tibetan Plateau

Abstract

Glacier detachment is a severe natural hazard that can cause enormous damage in downstream regions. During detachment, a glacier will experience an abrupt change from slow-moving to high-speed flow within minutes. In this study, we investigate a massive glacier detachment event that occurred in 2018 in the Sedongpu Valley, southeastern Tibet, using a two-dimensional first-order ice flow model incorporating a positive feedback mechanism between ice stiffness and basal slip. In this model, detachment can be triggered if the ice stress exceeds the initial yield strength of glacier ice. By including this tipping mechanism, we simulate abrupt changes in the ice flow pattern of the Sedongpu Glacier. The transition from slow to abrupt flow occurs after most regions of the glacier reach a plastic state. The modeled duration of the 2018 Sedongpu detachment is comparable with observations. The abrupt weakening of ice strength during the transition from elastic to plastic deformation may be a primary cause of glacier detachment tipping processes.