KATHMANDU: German alpinist Jost Kobusch is preparing for his fourth attempt to climb Mount Everest in winter, aiming to reach the summit solo, without supplemental oxygen or support from guides above base camp, via the mountain's West Ridge.

The 34-year-old climber plans to begin the main phase of his expedition around December 22, continuing a project he started in 2019. He has described the uncertainty of the attempt as part of its appeal, saying he wants to test what is possible rather than assume success.

"The uncertainty is what makes it worth attempting," Kobusch wrote in a recent social media post, explaining that the project is driven by curiosity about the limits of preparation, judgement and experience in extreme conditions.

Kobusch has made three previous winter attempts, reaching about 7,540 metres during his 2024 expedition. Strong winds and concerns over weather and safety prevented him from continuing towards the summit. He is now preparing in Nepal, including climbing in the Annapurna region to improve acclimatisation.

His planned route follows the technically demanding West Ridge, which has not been climbed to Everest's summit in winter. Only 14 climbers have reached the 8,849-metre summit during the winter season by other routes, according to figures cited by Reuters.

Kobusch said his preparation also involved making decisions about climbing style and equipment. During a recent Chulu traverse, he wanted to climb without fixed ropes, while some companions chose to use them. He said he had been learning to respect others' decisions while remaining clear about his own approach to the Everest project.

Winter conditions on Everest bring extreme cold, powerful winds and shorter daylight hours. Temperatures above 8,000 metres can fall to minus 40 degrees Celsius or lower, making the attempt particularly demanding.

Kobusch's objective is to combine a winter ascent with solo climbing, no supplemental oxygen and no guide or Sherpa support above base camp. Whether he can reach the summit by the West Ridge remains uncertain.