Abstract
In December 2014, an ice jam occurred on the Osobetsu River after a snowstorm. This study investigated factors that contribute to increases in frazil slush and identified locations prone to ice jams. Previous studies using a hydraulic model experiment showed that an ice sheet's Froude number become small where ice sheets are static or accumulated. Moreover, a frazil slush calculation model that is based on the theory of heat balance in stream water accurately reproduced the measured thickness of frazil slush. However, no previous studies on ice jams have taken into account the Froude numbers of ice sheets. Also, certain weather phenomena, such as snowstorms and avalanches, are not factored into the current model for calculating frazil slush thickness. Therefore, the authors developed the model such as to take into account the effect of snowstorms. Furthermore, we used the Froude number of the ice sheet to identify potential ice jam locations on the Osobetsu River.
