Combined with the precipitation forecast based on the NCFP GFS model on July 27, 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. NCEP GFS precipitation forecast shows that there will be less rainfall along the Karakoram Highway on July 27, mainly concentrated in the southern region, with cumulative rainfall reaching 16 mm (figure 1). This amount of rainfall is roughly on par with that of July 26th and is not extreme overall. 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 (Figure 2) show that due to the significantly lower rainfall on the 26th and 27th, the overall spatial pattern of the high-risk areas remains basically consistent, but the coverage area has been reduced, mainly concentrated in the sections north of Chilas. The extremely high and highly prone areas are still distributed in a band-like pattern along the main river valley corridors in the north, and the distribution areas are mostly mountainous zones with intense terrain undulations and deep rivers. Around Chilas, Gilgit, Chalt, Nagar and other places, steep slopes are densely distributed and the foot of the slopes is close to major rivers and traffic arteries, resulting in a phenomenon of high-value aggregation in some local areas. In contrast, the area south of Chilas, the transition zone of valleys and the mountains with gentler slopes are mostly of medium susceptibility. The overall distribution is relatively scattered and shows local patchy characteristics.
From the results of susceptibility, it can be seen that the areas around Muzaffarabad in the south of KKH, the Chila-Dashkin and Gilgit-Hunza-Passu corridors along KKH, and the sections north of Passu, which are highly prone to occurrence, should be regarded as key risk zones. Special attention should be paid to disasters such as high and steep slopes and mudslides during and after rainfall.
结合 2025 年 7 月 27 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 27 日喀喇昆仑公路沿线降雨较少，主要集中于南部地区，累积雨量达 16 mm（图1）。这一降雨量大致与7月26日持平，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），由于26、27日降雨量明显较低，高易发区域的总体空间格局 基本保持一致，但覆盖范围有所缩减，主要集中在 Chilas 以北的路段。极高及高易发区依然沿北部主要河谷走廊呈带状分布，分布区域多为地形起伏剧烈、河流深切的山地带。Chilas、 Gilgit、Chalt、Nagar 等地周边，陡坡密布且坡脚紧邻主要河道和交通干线，局部区域形成 高值聚集现象。相比之下，Chilas以南区域、谷地过渡带及坡度较缓的山体多为中等易发等级，整体分布较为零散，并呈现局部斑块状特征。
从易发性结果可以看出，KKH南部的Muzaffarabad 周边地区、沿 KKH 穿越的 Chilas-Dashkin、Gilgit—Hunza—Passu 走廊 、Passu 以北段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。
