This study attempted to analyze tsunami evacuation behavior issues using trajectory data obtained via satellite positioning system in a heavy snow and cold area. This study chose Kushiro, Hokkaido as the research area, as this city has the largest population among the Hokkaido costal municipalities where tsunamis may be expected to occur. The mobile trajectory data were recorded with a handheld GPS (global positioning system) device in summer and in winter, and analyzed to compare summer and winter data. The mobile trajectory data were visualized by kernel density estimation focused decreases in walking speed using GIS (geographic information system). As a result, it was established that obstacles to the evacuation were different in summer and in winter. The study suggests the need to evaluate tsunami evacuation measures by season.