Risk assessment of glacial lake outburst flood in the Central Asian Tienshan Mountains

Global warming has accelerated alpine glacier melting and led to an increased risk of glacial lake outburst floods (GLOFs). This paper extracted glacial lake boundaries in the Tienshan Mountains of Central Asia from 1990 to 2023, analyzed their spatiotemporal variations and evaluated their risk levels under current and future scenarios. The results show that glacial lakes are predominantly distributed in the Central and Western Tienshan, accounting for 75% of the total number in the Tienshan region. The number and area of glacial lakes increased by 148% (from 1837 to 4557) and 71.83% (from 119.73 to 205.73 km2) during 1990 to 2023, with moraine lake expansion predominating. In the Western Tienshan, the high or very high risk of GLOF is 3–4 times that of other areas. By the middle of the twenty-first century, GLOF risk will continue to increase, especially in the Western Tienshan. This study can provide scientific foundation for disaster mitigation in the downstream areas.