Characteristics of debris-covered snow-covered gorge during the snowmelt period in the Northern Japan Alps

We introduce the result of field observation associated with debris-covered snow-covered gorge in the Japanese Alps incorporating the effects of high mountain climate and extreme environment. The Japanese Alps strata that form the slopes and piedmonts of the extreme mountainous environments are highly erodible, which determines the specific features on the shrinkage of snow-covered gorges. In this study, we report the characteristics of debris-covered snowy gorges during the beginning of the snowmelt period in the extreme mountainous environment region of the Japanese Alps. We measured the temperature profiles and daily variations in typical nutrient parameters at debris-covered gorge and bare-ice glacier in the Kekachi valley in the northern Japan Alps of north-central region in Japan, to assess the characteristics association with the effect of debris-covered snowy gorge. The Kekachi valley is a typical snowy gorge region in Japan and also in the world that is located on the northern Japan Alps and lies over the Holocene sediment of the median tectonic line on Honshu Island, Japan. The debris covered snowy gorge remains almost throughout the year. This study indicated that the effect of debris coverage on the shrinkage of snow-covered gorges results in how the gorges respond to high mountain climate and environment of the Japanese Alps. We also compared debris-covered snowy area and bare ice area. Our results indicated that the highest ground surface temperature within 10 cm varied from 8 °C to 15 °C, having diurnal cycle for the crucial baseline factor associated with the existence of debris-covered snow-covered gores. Although, the growing meltwater discharge and surface lowering indicates that such snowy gorges are currently shrinking, their fronts remain remarkably stable, as also been observed in other regions.