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Combined barometric pressure (BP) and wind chill temperature (WCT). Sample size – 499 ascents without supplemental oxygen and 29 with oxygen support (1978–2021). Dashed line box covers ascents in combined conditions of BP ≤ 346 hPa and WCT ≤ −54°C, gray area represents ascents in combined conditions of BP ≤ 333 hPa and WCT ≤ −54°C.
