The impact of rain-on-snow events on the snowmelt process: A field study

Previous studies have primarily focused on the hydrological response of snowpack during rain-on-snow (ROS) events, with limited attention given to their subsequent stages, despite the significance of these stages. Therefore, this study selected two snow plots with similar initial parameters in the Qilian Mountains at an altitude of 4151 m. One of the snow plots underwent artificial rainfall simulation, and the changes in snow albedo, liquid water content, and snow depth of two snow plots were observed and analysed during the rainfall experiment and for a period of 7 days thereafter. The results indicate that ROS events significantly accelerate the rate of decrease in snow albedo and snow depth, increase the liquid water content within the snowpack, and these effects persist for several days after the rainfall event. Furthermore, the input of liquid water leads to rapid saturation of the snowpack, altering the transport mechanism of water within the snowpack, and transforming a process that would otherwise take a long time to complete into a short time. The decrease in snow albedo enhances the absorption of more energy by the snow, thereby accelerating snowmelt. Compared to natural snowmelt, ROS events cause the snowpack with high liquid water content to rapidly melt over a short period, resulting in a rapid increase in river flow, which may be one of the causes of ROS-induced flooding. These research findings provide scientific insights for a better understanding of the disaster mechanisms associated with ROS events. Rain-on-snow (ROS) events significantly accelerate the rate of decrease in snow albedo and snow depth, increase the liquid water content within the snowpack, and these effects persist for several days after the rainfall event. Compared to natural snowmelt, ROS events cause high liquid water content in the snowpack to rapidly melt over a short period, resulting in a rapid increase in river flow, which may be one of the causes of ROS-induced flooding.image