薄曇り日中は穏やか稜線午後に風強まる

Mount Poroshiri starts with partly cloudy skies this morning, with temperatures expected to rise during the day, offering relatively mild conditions for ascent. The temperature difference between the summit and the base is significant at 8.8°C, with the summit currently at 5.6°C, feeling like 2.6°C. While the feels-like temperature is projected to rise to 2.8°C by 09:00 and 3.2°C by 12:00, the ground condition near the summit will be a mix of residual snow and exposed rock. The warming temperatures will soften the snow, potentially creating muddy sections. For the Nukabiragawa Course, which involves over 20 river crossings, there is no forecast for heavy precipitation, so the risk of flash floods is low. However, increased water volume from snowmelt and swift currents should be noted. Waterproof gear and footwear with good grip are essential.

Winds will intensify in the afternoon, with gusts reaching 14.1 m/s by 15:00, making the feels-like temperature drop to near 0°C. Winds will be particularly strong in the exposed cirque areas. As indicated by the automatic risk assessment, a rapid temperature drop of 7°C is expected during the forecast period. Therefore, carrying an extra insulation layer from the start is crucial to prepare for sudden changes in conditions. The risk of hypothermia will increase, so early action and prompt decision-making to turn back are paramount. Activity after sunset should be avoided.

Essential gear includes a three-layer system: a quick-drying base layer, an insulating mid-layer (fleece or light down), and a waterproof-breathable outer shell. Warm accessories such as gloves, a hat, and a neck warmer should also be carried. While crampons are not strictly necessary due to the minimal snow depth, carrying light crampons or microspikes could provide added security. This is an active season for brown bears, so bear bells and bear spray are indispensable precautions.