独立峰の雨と霧。森林限界以上は低体温に注意

Yotei-zan summit is currently cloudy with a real feel temperature of 10.1 degrees Celsius, a significant difference from the base. Throughout the day, light drizzle will transition to light rain, with precipitation probability reaching 98% by 3 PM. Although the air temperature hovers around 10 degrees Celsius, the high humidity of 87% combined with rain will drastically lower the perceived temperature. While average wind speeds are low, gusts will exceed 12 m/s, increasing to 16 m/s overnight.

Continuous precipitation will render the ground wet and muddy. Steep sections, such as those on the Hirafu route and Makari route, will become particularly slippery, increasing the risk of falls. Above the forest limit at 1400m, exposed to the strong winds and rain characteristic of an isolated peak like Yotei-zan, the risk of hypothermia becomes extremely high. Current visibility is 5.2km, but it is likely to deteriorate rapidly due to rain and fog. Traversing the crater rim, known as O-hachi-meguri, poses a severe risk of slipping and falling in these conditions.

Anyone considering an ascent must carry full waterproof and breathable rain gear, mid-layers like fleece, and insulating layers such as a light down or synthetic jacket, gloves, and a hat. Real feel temperatures will drop to around 8 degrees Celsius even during the day, making sustained activity difficult without adequate insulation. Crampons or microspikes are not necessary, but footwear providing good traction on slippery surfaces is essential.

Hiking is not recommended under these conditions. Ascending above the forest limit carries particularly high and compounded risks of hypothermia, disorientation due to poor visibility, and falls. As temperatures are forecast to drop to 8 degrees Celsius overnight with heavy showers and strong gusts, avoid any activity after sunset.