利尻山 曇天と低温。脆い火山礫に足元注意

Rishiri-zan summit is currently cloudy with a temperature of -1°C, feeling like -6.3°C due to wind chill. The temperature difference between the summit and the base is approximately 9.5°C, indicating the characteristic chill of an isolated peak. While temperatures are expected to slightly rise during the day, the wind chill will remain below freezing throughout. Winds are around 5m/s, but gusts will exceed 12m/s, potentially reaching 13m/s around noon.

There is no snow cover. However, from the 9th station to the summit, loose volcanic gravel is exposed. The combination of low temperatures and strong gusts makes maintaining balance challenging, increasing the risk of rockfall and slips due to unstable footing. Extreme caution is required, especially during descent. The unique conditions of Rishiri-zan, an isolated island mountain, mean that sea winds contribute to low temperatures, and the brittle volcanic gravel exacerbates unstable ground conditions.

The risk of hypothermia is high. With wind chill consistently below freezing, essential layering includes a wicking base layer (synthetic or merino wool), a mid-layer of fleece and a light down jacket, and a waterproof/windproof shell jacket and pants. Gloves, a hat, and a neck warmer are also crucial. While the risk of lightning is low, light drizzle is forecast from 6 PM, accompanied by further temperature drops. Getting wet will significantly lower your body temperature. Day trips are strongly recommended. Overall, climbing is possible with proper gear and a cautious plan, but thorough preparation for the unstable volcanic gravel above the 9th station and for low temperatures is paramount.