The relationships between the formation of accumulation terraces and climatic changes, especially changes in the mountain permafrost environment, were investigated in the upper reaches of the Gamata River on the western side of the Yari-Hotaka Mountains, northern Japanese Alps. Optically stimulated luminescence (OSL) dating of these river terrace deposits is now in progress. The present distributions of mountain permafrost and permafrost-related landforms (e.g. rock glaciers) were investigated around Mt. Shirouma, located in the northern part of the northern Japanese Alps, and Mt. Suisyo, located in the central part of the northern Japanese Alps. The low bottom temperature of the winter snow cover (BTS <- 3 °C) and the negative mean annual ground surface temperature (MAST) on the blocky landform (protalus lobe) in the Suisyo C cirque indicate the presence of permafrost.
