羊蹄山 快晴から霧雨へ 独立峰の急変に備えよ

Yotei Summit currently enjoys clear skies with visibility exceeding 20km, offering excellent views. The temperature is 4.7 degrees Celsius, feeling like 1.9 degrees Celsius with almost no wind. These calm conditions are expected to persist until around 9 AM, but a temperature difference of over 10 degrees Celsius already exists between the summit and base, necessitating constant vigilance for rapid weather changes characteristic of an isolated peak.

Around noon, light mist and drizzle are forecast to begin, with wind speeds reaching 3.71 meters per second and gusts up to 12.5 meters per second. Although the temperature will rise to 8.7 degrees Celsius, the wind chill factor will be significant. Above the 1400m treeline and particularly along the crater rim, these gusts pose a risk of losing balance. If attempting the Ohatsu-meguri (crater rim traverse), continuously monitor wind conditions and avoid unnecessary risks.

A sharp temperature drop of nearly 8 degrees Celsius is expected during the forecast period. Temperatures will plummet in the evening, reaching below freezing overnight. For extended activities, the risk of hypothermia becomes very high in areas above the treeline. Carry an extra insulating layer from the start and make early decisions to turn back. With no current snow cover, the ground is likely wet to muddy due to the forecast precipitation. Waterproof hiking boots and full rain gear are essential.