残雪期の雄山 終日快晴で登山日和

At 7 AM, Mt. Oyama's summit, at 2993 meters, is clear with a temperature of 4.1°C and a feels-like temperature of 1.2°C. Winds are light and visibility is excellent. Temperatures are expected to rise significantly, reaching 12.8°C by noon. In this late spring period, the remaining snow, currently 169cm deep, will be firm and potentially slippery in the early morning, but will quickly soften under the day's sun. The ascent from Ichinokoshi presents an increased risk of rockfall as the snow melts and rocks become unstable. Pay close attention to stones dislodged by climbers ahead and loose rocks compromised by thaw.

The route from Murodo via Ichinokoshi to the summit of Mt. Oyama still retains substantial snow cover. Crampons or microspikes are essential due to the variable snow conditions. As the day progresses, the snow will become slushy, making footing precarious. Ground conditions will be a mix of residual snow, exposed rock ridges, and wet or muddy sections due to meltwater. A waterproof and windproof outer layer is mandatory. For layering, wear a fast-drying synthetic or wool base layer, a fleece mid-layer, and always carry a spare insulated jacket (down or synthetic) for additional warmth. The risk of lightning and strong winds is low.

The automated risk assessment indicates a sharp temperature drop of 8°C during the forecast period. Sweating during daytime activity combined with falling temperatures in the evening increases the risk of hypothermia, especially on 3000-meter peaks. Adjust your layers frequently for thermal regulation and change out of any wet clothing promptly. Given the easy access via the Alpine Route, expect crowds on clear days, and congestion on the route can lead to prolonged exposure and increased hypothermia risk. Make early decisions to turn back if conditions warrant.