Environmental conditions at the South Col of Mount Everest and their impact on hypoxia and hypothermia experienced by mountaineers

Moore, G. W. K.; Semple, John L.; Cristofanelli, Paolo; Bonasoni, Paolo; Stocchi, Paolo

doi:10.1186/2046-7648-1-2

Cited by 5 publications

(7 citation statements)

References 25 publications

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“…Everest without supplemental oxygen in winter has been raised before but based on ∼324 hPa to characterize summit pressure ( Garrido et al, 2019 ; West, 1999 ). Our reconstruction emphasizes that this value may be an appropriate descriptor of average conditions, but highlights the possibility of much lower pressures still, agreeing with previous research in noting the importance of variability (weather) around the mean ( Moore and Semple, 2004 , 2011 ; Moore et al., 2012 ).…”

Section: Discussionsupporting

confidence: 91%

Into Thick(er) Air? Oxygen Availability at Humans' Physiological Frontier on Mount Everest

et al. 2020

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Global audiences are captivated by climbers pushing themselves to the limits in the hypoxic environment of Mount Everest. However, air pressure sets oxygen abundance, meaning it varies with the weather and climate warming. This presents safety issues for mountaineers but also an opportunity for public engagement around climate change. Here we blend new observations from Everest with ERA5 reanalysis (1979-2019) and climate model results to address both perspectives. We find that plausible warming could generate subtle but physiologically relevant changes in summit oxygen availability, including an almost 5% increase in annual minimum VO 2 max for 2 C warming since pre-industrial. In the current climate we find evidence of swings in pressure sufficient to change Everest's apparent elevation by almost 750 m. Winter pressures can also plunge lower than previously reported, highlighting the importance of air pressure forecasts for the safety of those trying to push the physiological frontier on Mt. Everest.

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Section: Discussionsupporting

confidence: 91%

Into Thick(er) Air? Oxygen Availability at Humans' Physiological Frontier on Mount Everest

et al. 2020

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“…Low BP, low Temp and high Wind are the main environmental factors that limit human performance and survival at high altitude ( West and Wagner, 1980 ; West et al, 1983a , 2007b ; Huey et al, 2001 ; Huey and Eguskitza, 2001 ; Moore and Semple, 2012 ; Moore et al, 2012 ). We aimed to evaluate weather extremes in the Death Zone and to determine the most severe environmental conditions that mountaineers have experienced.…”

Section: Discussionmentioning

confidence: 99%

“…BP imposes the main limit on physiological performance at high altitude because it determines the critically important partial pressure of inspired oxygen, maximum oxygen uptake and speed of vertical ascent ( Pugh et al, 1964 ; West and Wagner, 1980 ; West, 1983 , 2000 ; West et al, 1983a , b , 2007b ; Sutton et al, 1988 ; Bailey, 2001 ; Matthews et al, 2020b ). Low temperatures and high winds significantly compound physiological stress at extreme altitudes ( Huey et al, 2001 ; Huey and Eguskitza, 2001 ; McIntosh et al, 2008 ; Moore and Semple, 2011 , 2012 ; Moore et al, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

“…Meteorological data for the conditions endured while climbing in the Death Zone are usually restricted to single weather factors on Everest ( West et al, 1983b ; West, 1999 ; Moore and Semple, 2004 ; Grocott et al, 2010 ; Moore et al, 2012 ; Moore and Semple, 2012 ; Matthews et al, 2020b ). The estimated average climbing-season BP on Everest is 333 hPa, dropping to 323 hPa in midwinter ( Matthews et al, 2020b ).…”

Section: Introductionmentioning

confidence: 99%

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Death Zone Weather Extremes Mountaineers Have Experienced in Successful Ascents

et al. 2021

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BackgroundFew data are available on mountaineers’ survival prospects in extreme weather above 8000 m (the Death Zone). We aimed to assess Death Zone weather extremes experienced in climbing-season ascents of Everest and K2, all winter ascents of 8000 m peaks (8K) in the Himalayas and Karakoram, environmental records of human survival, and weather extremes experienced with and without oxygen support.Materials and MethodsWe analyzed 528 ascents of 8K peaks: 423 non-winter ascents without supplemental oxygen (Everest–210, K2–213), 76 ascents in winter without oxygen, and 29 in winter with oxygen. We assessed environmental conditions using the ERA5 dataset (1978–2021): barometric pressure (BP), temperature (Temp), wind speed (Wind), wind chill equivalent temperature (WCT), and facial frostbite time (FFT).ResultsThe most extreme conditions that climbers have experienced with and without supplemental oxygen were: BP 320 hPa (winter Everest) vs. 329 hPa (non-winter Everest); Temp –41°C (winter Everest) vs. –45°C (winter Nanga Parbat); Wind 46 m⋅s–1 (winter Everest) vs. 48 m⋅s–1 (winter Kangchenjunga). The most extreme combined conditions of BP ≤ 333 hPa, Temp ≤ −30°C, Wind ≥ 25 m⋅s–1, WCT ≤ −54°C and FFT ≤ 3 min were encountered in 14 ascents of Everest, two without oxygen (late autumn and winter) and 12 oxygen-supported in winter. The average extreme conditions experienced in ascents with and without oxygen were: BP 326 ± 3 hPa (winter Everest) vs. 335 ± 2 hPa (non-winter Everest); Temp −40 ± 0°C (winter K2) vs. −38 ± 5°C (winter low Karakoram 8K peaks); Wind 36 ± 7 m⋅s–1 (winter Everest) vs. 41 ± 9 m⋅s–1 (winter high Himalayan 8K peaks).Conclusions1.The most extreme combined environmental BP, Temp and Wind were experienced in winter and off-season ascents of Everest.2.Mountaineers using supplemental oxygen endured more extreme conditions than climbers without oxygen.3.Climbing-season weather extremes in the Death Zone were more severe on Everest than on K2.4.Extreme wind speed characterized winter ascents of Himalayan peaks, but severely low temperatures marked winter climbs in Karakoram.

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“…Meteorological factors that limit human survival at the top of Everest—such as barometric pressure (BP), wind chill equivalent temperature (WCT), and facial frostbite time (FFT)—have already been assessed with meteorological datasets and in situ observations [ 9 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. The estimated average monthly BP in May on Everest, its main climbing season, is 333 hPa, and in midwinter in January and February, it is 323 hPa [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Environmental Conditions on Summits of Mount Everest and K2 in Climbing and Midwinter Seasons

Szymczak

Pyka

Grzywacz

et al. 2021

IJERPH

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(1) Background: Today’s elite alpinists target K2 and Everest in midwinter. This study aimed to asses and compare weather at the summits of both peaks in the climbing season (Everest, May; K2, July) and the midwinter season (January and February). (2) Methods: We assessed environmental conditions using the ERA5 dataset (1979–2019). Analyses examined barometric pressure (BP), temperature (Temp), wind speed (Wind), perceived altitude (Alt), maximal oxygen uptake (VO2max), vertical climbing speed (Speed), wind chill equivalent temperature (WCT), and facial frostbite time (FFT). (3) Results: Most climbing-season parameters were found to be more severe (p < 0.05) on Everest than on K2: BP (333 ± 1 vs. 347 ± 1 hPa), Alt (8925 ± 20 vs. 8640 ± 20 m), VO2max (16.2 ± 0.1 vs. 17.8 ± 0.1 ml·kg−1·min−1), Speed (190 ± 2 vs. 223 ± 2 m·h−1), Temp (−26 ± 1 vs. −21 ± 1°C), WCT (−45 ± 2 vs. −37 ± 2 °C), and FFT (6 ± 1 vs. 11 ± 2 min). Wind was found to be similar (16 ± 3 vs. 15 ± 3 m·s−1). Most midwinter parameters were found to be worse (p < 0.05) on Everest vs. K2: BP (324 ± 2 vs. 326 ± 2 hPa), Alt (9134 ± 40 vs. 9095 ± 48 m), VO2max (15.1 ± 0.2 vs. 15.3 ± 0.3 ml·kg−1·min−1), Speed (165 ± 5 vs. 170 ± 6 m·h−1), Wind (41 ± 6 vs. 27 ± 4 m·s−1), and FFT (<1 min vs. 1 min). Everest’s Temp of −36 ± 2 °C and WCT −66 ± 3 °C were found to be less extreme than K2’s Temp of −45 ± 1 °C and WCT −76 ± 2 °C. (4) Conclusions: Everest presents more extreme conditions in the climbing and midwinter seasons than K2. K2’s 8° higher latitude makes its midwinter BP similar and Temp lower than Everest’s. K2’s midwinter conditions are more severe than Everest’s in the climbing season.

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Environmental conditions at the South Col of Mount Everest and their impact on hypoxia and hypothermia experienced by mountaineers

Cited by 5 publications

References 25 publications

Into Thick(er) Air? Oxygen Availability at Humans' Physiological Frontier on Mount Everest

Into Thick(er) Air? Oxygen Availability at Humans' Physiological Frontier on Mount Everest

Death Zone Weather Extremes Mountaineers Have Experienced in Successful Ascents

Comparison of Environmental Conditions on Summits of Mount Everest and K2 in Climbing and Midwinter Seasons

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