EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2026-4065 Brief communication: Repeated supraglacial lake drainage from the Purepu Glacier system, central Himalaya Xu Qiangqiang 1 3 Kang Shichang 2 Du Wentao 1 3 Wu Wei 4 Hu Zhaofu 1 3 He Xiaobo 5 Cao Bo 6 7 Xie Biwen 6 State Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Mountain Hazards and Engineering Resilience, Institute of Mountain Hazard and Environment, Chinese Academy of Sciences, Chengdu 610213, China Qilian Mountains Field Research Station for Interactions among Cryosphere and Multi-spheres, China Meteorological Administration. Lanzhou 730000, China Department of Disaster Assessment, National Disaster Reduction Centre of China, Ministry of Emergency Management, Beijing 100124, China Tanggula Mountain Cryosphere and Environment Observation and Research Station of Tibet Autonomous Region, State Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China Key Laboratory of Western China’s Environmental Systems (MOE), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China Gansu Shiyang River Basin Scientific Observing Station, Lanzhou 730000, China 12 08 2026 2026 1 14 Copyright: © 2026 Qiangqiang Xu et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4065/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4065/egusphere-2026-4065.pdf

We report repeated drainage from the Purepu supraglacial lake system in the central Himalaya using high-resolution satellite imagery. A satellite-inferred 2023 drainage event is constrained to 12–15 July, whereas a reported GLOF occurred early on 8 July 2025. Both followed lake expansion to ~0.70–0.72 km², but DEM-constrained lake-volume loss increased from 0.87 × 10⁶ m³ in 2023 to 3.55 × 10⁶ m³ in 2025. The 2025 event remained incomplete, and flood-volume reconstruction suggests additional englacial or subglacial contributions cannot be excluded. Residual water persisted into 2026, supporting high-frequency monitoring in early July 2026.

 Science and Technology Plan Projects of Tibet Autonomous Region XZ202601ZD0014 Science and Technology Department of Tibet Autonomous Region XZ202601ZY0187 Science and Technology Department of Gansu Province 24ZD13FA003