周期性形成的克亚吉尔冰川阻塞湖突然排水导致的洪水灾害对下游构成严重威胁。在全球气候变暖背景下，开展克亚吉尔冰川阻塞湖的监测预警研究尤为必要。本文基于1990—2023年的多源光学遥感数据，分析了克亚吉尔冰川阻塞湖面积变化以及突然排水情况，利用面积-体积经验公式和历史洪水数据，以最小排水体积为临界值，推算出克亚吉尔冰川阻塞湖突发洪水的警戒湖面面积。同时，通过建立排水体积与净洪峰流量的关系，验证了警戒面积的合理性。结果表明：克亚吉尔冰川阻塞湖在过去的34 a间共发生了20次突然排水事件，其中17次形成突发洪水，1996—2009年和2015—2019年是反复蓄水和排水的两个不稳定期。冰湖警戒面积为1.046 km²，其突然排水产生的净洪峰流量为418 m³·s^-1。尽管克亚吉尔冰川阻塞湖面积呈下降趋势，但其引发的洪水灾害风险并未降低，克亚吉尔冰川阻塞湖突发洪水与基本径流叠加仍可能对下游构成威胁。当冰湖面积接近警戒面积时，应密切监测冰湖的变化，同时结合水文站基本径流情况进行早期预警。本研究提出的警戒面积指标及其确定方法为克亚吉尔冰川阻塞湖突发洪水的预警监测提供了科学支撑，对叶尔羌河流域洪水灾害预警有一定参考意义。

The periodic outburst floods from the Kyagar Glacier-dammed Lake pose a severe threat to downstream areas. In the context of global warming, research on monitoring and early warning for the Kyagar Glacier-dammed Lake is particularly important. Therefore, this study aimed to determine the alert area for the Kyagar Glacier-dammed Lake outburst floods. The area changes and sudden drainage events of the lake were first analyzed using multi-source optical remote sensing data from 1990-2023. Then, the critical minimum drainage volume of the lake was calculated using an area-volume empirical formula and historical flood data. At the same time, the rationality of the alert area was verified through the relationship between the drainage volume and the net flood peak discharge established in this study. The results showed that the lake experienced 20 sudden drainage events over the past 34 years, 17 of which led to glacial lake outburst floods. The periods 1996-2009 and 2015-2019 were unstable, with repeated lake filling and draining. The alert area for the outburst floods of the Kyagar Glacier-dammed Lake is 1.046 km², and the alert net flood peak discharge resulting from the sudden drainage is 418 m³·s^-1. Although the lake area shows a decreasing trend, the risk of flood disasters triggered by the Kyagar Glacier-dammed Lake outburst floods does not necessarily decrease. The lake outburst flood, when superimposed on high basic runoff, can still threaten downstream areas. When the lake area approaches its alert area, it is necessary to monitor its changes closely and implement early warning measures in combination with the basic runoff at the hydrological station. The proposed alert lake area and its determination method may provide scientific support for early warning monitoring of the outburst flood of the Kyagar Glacier-dammed Lake and offer guidance for early warning of flood disasters in the Yarkand River Basin.