独立峰の強風と冷気。森林限界超は低体温に注意

Current conditions at the summit of Mt. Yotei are cloudy with an air temperature of 1.7℃ and a felt temperature of -2.6℃. Strong southerly winds are present, with gusts reaching 14.4m/s. The temperature difference from the base is over 10℃, indicating winter-like conditions persist at the summit. While temperatures will gradually rise during the day, gusts are expected to reach 18.7m/s by noon. Apparent temperatures will remain near or below freezing throughout the day, necessitating proper cold weather gear.

Snow depth is 0cm, and no precipitation is forecasted. The ground is generally dry, but due to the strong winds characteristic of an isolated peak, hikers on exposed slopes above the tree line (around 1400m) on routes like Hirafu or Makari should be wary of swirling dust and small stones. Essential layering includes a wicking synthetic or merino wool base layer, a fleece or light down mid-layer, and a windproof and waterproof shell for the outer layer. Gloves, a hat, and a neck warmer are also mandatory. Crampons or microspikes are not required, but sturdy trekking shoes with good grip are recommended.

Today's gusts of 18.7m/s are strong enough to make progress difficult, especially on exposed areas like the crater rim traverse (O-hachi-meguri), where the risk of falling is significantly elevated. Prolonged exposure to these strong winds increases the risk of hypothermia; therefore, frequent breaks, adequate nutrition, and making turn-around decisions in sheltered spots are crucial. The risk of lightning is low. Winds will subside in the evening, but temperatures will drop to 0℃ by midnight and -0.6℃ by early morning, with a forecast for light drizzle, which could further reduce felt temperatures.