濃霧と霧雨が終日続く。道迷いと低体温症に厳重警戒

Tomuraushi summit is currently enveloped in dense fog with visibility less than 1km, under cloudy skies. The temperature is 4.5 degrees Celsius, feeling like 2.4 degrees Celsius. There is a significant temperature difference of about 10 degrees from the base, indicating much colder conditions at higher elevations. Light drizzle will persist throughout the day, with temperatures reaching a maximum of 7.8 degrees Celsius, but wind gusts could make the effective temperature drop below freezing. This makes rock gardens and other rocky sections particularly slippery due to wet surfaces.

During the main hiking hours from 9 AM to 3 PM, intermittent light rain is expected. High humidity combined with getting wet significantly increases the risk of hypothermia. Navigation becomes extremely challenging in areas like Kitnuma and Minaminuma wetlands, where poor visibility can easily lead to disorientation. Recalling the 2009 accident, weather changes in this mountain range can be as severe as those in 3000-meter peaks on Honshu. As indicated by the automatic risk assessment, a rapid temperature drop of 7 degrees Celsius is anticipated during the forecast period. Therefore, carrying waterproof and breathable outer layers, along with insulating layers like fleece or a light down jacket, is crucial to stay dry and warm.

Ground conditions will be generally wet and muddy due to the drizzle and high humidity. Rocky sections will be slick, requiring careful foot placement. While there is no snow, so crampons or microspikes are not needed, waterproof hiking boots, gloves, and a hat are essential. Adequate food, a headlamp, map, and GPS are also critical for safety. Given the mountain's reputation as a long and challenging course, especially with the expected adverse weather, prudent planning and the willingness to turn back are paramount.