The impact of debris flow is not only limited to the source area but it is also significantly governed by the runout. It is evident in many parts of the world, and it is also a usual phenomenon in the Himalayan environment. Even though a significant body of scientific work was concentrated on landslide susceptibility in this region, studies focused on the debris flow runout assessment are still scarce. Therefore, this study aims to develop a debris flow susceptibility assessment in the Kalimpong region (Himalaya, India) by integrating the initiation and runout areas. Additionally, the changes in exposed elements for different susceptibility zones are analysed between 2006 and 2018. The methodological framework considers two different approaches: the modelling of debris flow initiation based on the logistic regression method and the assessment of the runout using the Flow-R model. Regarding the debris flow initiation, the logistic regression model comprises eleven conditioning factors and shows an area under the receiver operating characteristic curve of 0.88. For the runout assessment, 139 models are simulated for selecting Flow-R parameters. The best combination of the Holmgren exponent of 4, the travel angle of 5° and the velocity of 13 m s⁻¹ produced the model with a true positive rate of 86.6% for the whole area. The final debris flow susceptibility model is generated by integrating the initiation and the runout areas. Lastly, a substantial change of buildings (+18%), roads (+27%) and agricultural land (−12%) can be found within the debris flow susceptible areas between 2006 and 2018.

泥石流的影响不仅限于源区，而且在很大程度上受径流控制。它在世界许多地方都很明显，在喜马拉雅环境中也是常见的现象。尽管大量的科学工作集中在该地区的滑坡敏感性上，但专注于泥石流径流评估的研究仍然很少。因此，本研究旨在通过整合起始区和径流区，在 Kalimpong 地区（印度喜马拉雅山）开展泥石流敏感性评估。此外，还分析了 2006 年至 2018 年期间不同敏感区暴露元素的变化。 方法框架考虑了两种不同的方法：基于逻辑回归方法的泥石流启动建模和使用 Flow-R 模型的跳动评估。关于泥石流的发生，逻辑回归模型包含 11 个条件因子，并显示接收器操作特征曲线下的面积为 0.88。对于跳动评估，模拟了 139 个模型以选择 Flow-R 参数。Holmgren 指数为 4、行进角为 5° 和速度为 13 m s 的最佳组合⁻¹生成的模型在整个区域的真阳性率为 86.6%。最终的泥石流敏感性模型是通过整合起始区和径流区生成的。最后，在 2006 年至 2018 年间，泥石流易发区的建筑物（+18%）、道路（+27%）和农用地（-12%）发生了重大变化。