Combined with the precipitation forecast based on the NCFP GFS model on July 26, 2025 and multi-source data such as lithology, DEM and hydrological conditions along the Karakoram Highway, the TRIGRS model was adopted to conduct the landslide risk assessment in the northern area which is greatly affected by rainfall. The NCEP GFS precipitation forecast shows that the national rainfall will decrease on July 26. The rainfall will be similar to that on July 25, concentrated in the western region, with local cumulative rainfall reaching 20 mm (figure 1). This rainfall has decreased compared to July 25th, and overall it is not extreme. However, it is during the peak period of the monsoon, and the continuous cumulative rainfall across the country has increased compared to the average of previous years. At this time, the infiltration of rainfall further increases the pore water pressure of the slope body, significantly reduces the effective stress and shear strength, and is prone to form a local saturated weak layer. These factors will cause the slope to rapidly evolve from the critical stable state to the instability threshold in the TRIGRS model, and the triggering probability of shallow collapses, slides or small debris flows will increase significantly.
The assessment results show (Figure 2) that the susceptibility results on July 26th are roughly similar to the spatial distribution of high-susceptibility areas on the 26th, but the range is somewhat reduced. The extremely high and high-susceptibility areas are still mainly distributed in a continuous band along the northern river valley corridor, concentrated in the mountainous areas with intense terrain undulations and strong river cuts. Around areas such as Chilas, Gilgit, Chalt and Nagar, steep slopes are dense and the foot of the slopes is close to major rivers or traffic arteries, and some local areas show high-value aggregation characteristics. In contrast, the transition areas of valleys and the gentle slopes are mostly of medium grade, with relatively scattered distribution and local patchy appearance.
From the results of susceptibility, it can be seen that high-susceptibility sections such as the Chilas-Dashkin and Gilgit-Hunza-Passu corridors along the KKH should be regarded as key risk areas, and special attention should be paid to disasters such as high and steep cutting slopes and mudslides during and after rainfall.
结合 2025 年 7 月 26日基于 NCFPGFS 模式的降水预报与喀喇昆仑公路沿线的岩性、DEM、水文条件等多源数据，采用TRIGRS模型，对收降雨影响较大的北部地区展开 滑坡危险性评估。NCEPGFS降水预报显示，7 月 26 日全国降雨量有所下降，降雨与7月 25 日相似，集中于西部地区，局地累积雨量达 20 mm（图1）。这一降雨量较7月25日有所回落，且整体并非极端，但正值季风高峰期间，全国持续累积降雨较常年有所提升。此时降雨入渗进一步提高了坡体孔隙水压力，显著降低了有效应力与抗剪强度，容易形成局部饱和薄弱层。这些因素在TRIGRS模型中将使边坡从临界稳定状态快速向失稳阈值演化，浅层崩塌、滑塌或小型泥石流的触发概率大幅上升。
评估结果显示（图2），7月26日易发性结果与25日高易发区空间分布大致相似，但在范围上有所减少。极高与高易发区仍主要沿北部河谷走廊呈连续带状分布，集中于地形起伏剧烈、河流强烈切割的山区。Chilas、Gilgit、Chalt、Nagar 等地段周边，陡坡密集且坡脚 紧邻主要河流或交通干线，局部区域显示出高值聚集特征。相较之下，谷地过渡区及低缓山 坡多表现为中等级，易发性分布相对零散，局部呈斑块状。
从易发性结果可以看出，沿 KKH 穿越的Chilas-Dashkin、 Gilgit—Hunza—Passu 走廊等高易发性路段应被视为重点风险区段，需重点关注在降雨过程中与雨后的高陡切坡、泥石流等灾害。
