Abstract: On July 8, 2025, a glacial lake outburst flood (GLOF) occurred in the Donglin Zangbo Basin along the China-Nepal border, triggering a cross-border debris flow. Due to the scarcity of in-situ measurements in this remote high-altitude region, in order to review the disaster process, multiple remote sensing images and Gaofen-7 (GF-7) topographic data were comprehensively used to reveal the rapid expansion of the glacial lake to 0.6 km² in the early stage of the outburst flood. The water level area storage capacity relationship of the glacial lake was extracted, and the total water storage capacity was estimated to be 8.0～8.5 million m³, with a total water discharge of 5.0～6.0 million m³ from the outburst flood. Based on remotely identified breach parameters, the peak discharge was calculated to be 1 100～1 400 m³/s, which aligns well with the hydrograph measured at a downstream gauging station. However, a discrepancy was observed between the remotely sensed outburst volume and the monitored flood volume downstream. This disparity suggests the potential involvement of internal water storage within the glacier and the entrainment of substantial solid materials from the channel. This study underscores the indispensable value of remote sensing for monitoring glacial lake dynamics and assessing GLOF risks in inaccessible high-mountain regions. It also highlights the complex mechanisms of GLOF-induced disaster chains and emphasizes the urgent need for developing integrated ground-penetrating and space-air-ground collaborative monitoring networks.