In 2005, the Japanese government launched a new nationwide early warning system for predicting debris flow and slope failure disasters based on rainfall intensity and the Soil Water Index (SWI). However, the Japanese government has not set early warning criteria in many mountain areas. In addition, the existing early warning criteria in some areas are much higher than realistic ones, and snowmelt water is not considered in the calculation of the SWI. These two factors have been the cause of many slope failures in seasonally cold regions, induced by rainfall and/or snowmelt, which were not predicted. Therefore, this study attempts to propose a new determination method for setting early warning criteria for rainfall- and/or snowmelt-induced slope failures in seasonally cold regions. For this purpose, the study firstly proposes a combination model for estimating snow density that incorporates the hourly snowmelt water into the Japanese early warning system more accurately by using meteorological monitoring data and modeled snow density. Next, based on case studies and parametric analyses for slope stability assessment, new early warning criteria are proposed for predicting three different patterns of slope failures under two typical types of precipitation (rainfall and snowmelt) conditions. Finally, a new determination method for setting early warning criteria in seasonally cold regions is proposed by referring to the existing early warning criteria near the target area, in accordance with the precipitation types and the local ground conditions of the slopes. Since the existing early warning criteria near the target area already take the effects of the variations in local geology and geography into account, the new determination method for early warning criteria can be applied to arbitrary areas in seasonally cold regions, without directly considering the local soil properties, in the actual design and maintenance works.

2005年，日本政府启动了一个新的全国性预警系统，该系统可根据降雨强度和土壤水分指数（SWI）预测泥石流和边坡破坏灾害。但是，日本政府尚未在许多山区设定预警标准。此外，某些地区现有的预警标准远高于现实标准，在计算SWI时未考虑融雪水。这两个因素是季节性寒冷地区由于降雨和/或融雪引起的许多边坡破坏的原因，这是无法预料的。因此，这项研究试图提出一种新的确定方法，为季节性寒冷地区的降雨和/或融雪引起的边坡破坏确定预警标准。以此目的，该研究首先提出了一种估计雪密度的组合模型，该模型通过使用气象监测数据和建模的雪密度，将每小时融雪水更准确地整合到日本预警系统中。接下来，基于案例研究和用于坡度稳定性评估的参数分析，提出了新的预警标准，用于在两种典型的降雨类型（降雨和融雪）条件下预测三种不同的边坡破坏模式。最后，提出了一种新的确定季节性寒冷地区预警标准的方法，该方法参考了目标地区附近的降水预警标准，并根据坡度的降水类型和当地地面情况而定。