Read article "Why Mt. Fuji in Winter is Dangerous even for Advanced Mountain Climbers"
"Moreover, near the top of the mountain, the slope is about 45 degrees and the ice is covered with ice, so even if you take a wind-resistant position, your body may be carried away by the gusts of wind.""Above all, in winter at Mt.Fuji, the ice patches are terrible and the wind is strong . The annual average wind speed is about 10 m/s. And since the atmospheric pressure at Winter Fuji is about 20 hpa lower, even though the altitude is 3776 m, it actually becomes an altitude of 4000 m.""The ice is so frozen that the crampon blade can't penetrate it at all . Then, I feel like I'm about to be blown away by the wind and I want to take a wind-resistant position, but if I do that, I'm going to slip and fall, so there's no way I can take a wind-resistant position.""This is why I said that climbing Mt. Fuji during the harsh winter season is more technically difficult than climbing the highest peaks on the seven continents (McKinley, Kilimanjaro, etc.) when the summer climate is stable."