午後から雨と視界不良。濡れた岩稜に注意

Morning conditions at Mt. Yari's summit (3158.05m) show mostly clear skies, but visibility remains poor, less than 1km. The temperature is 10.1℃, feeling like 9.5℃, with light winds. A significant 9.4℃ temperature difference from the base underscores the alpine environment's harshness. Daytime temperatures are expected to hover around 10℃.

A shift to light rain is forecast from noon, intensifying to strong drizzle by 3 PM with a 100% chance of precipitation. This rain will make the exposed rocky terrain wet and extremely slippery. Specifically, the chained sections and ladders on the "Hozaki" (summit ridge) of Mt. Yari will become very hazardous, increasing the risk of slips and falls. Poor visibility will further complicate route finding. It is strongly advised to complete passage through these challenging sections before the onset of afternoon rain.

While wind speeds are not a major concern today, with gusts up to 5.8m/s, the persistent rain from noon onward significantly elevates the risk of hypothermia. A full set of waterproof and breathable rainwear, waterproof gloves, and a warm hat are essential. Layering should include a wicking base layer, a light fleece mid-layer, and a waterproof shell. Carrying an additional warm layer for stops or colder conditions is recommended. Despite no specific thunder warnings, summer alpine environments are prone to sudden thunderstorms. Be vigilant for any signs of lightning and be prepared to descend from exposed ridges to a safer location if thunder is heard.

Light drizzle will continue into the evening, with temperatures dropping to the single digits. Taking refuge at the Yarigatake Sanso (hut) or planning an early return is advisable during the anticipated afternoon precipitation.