Weather on K2 during historic first winter ascent

On 16 January 2021, a team of Nepalese mountaineers claimed the last great prize of high altitude mountaineering with the first winter summit of K2. Here, we examine to what extent the weather on the “savage mountain” may have aided the intrepid climbers during their ascent. We find that, whilst the team had to endure brutal temperatures and winds earlier in the season, the arrival of an upper-level ridge on 16 January brought uncharacteristically high pressures and temperatures, but low winds. Notably, the cold hazard was still extreme by the standards of summit climbs of mountains above 8,000 m a.s.l., but uncharacteristically favourable for K2 in winter. Extraordinary ability therefore aligned with a weather window of opportunity to set up this moment of mountaineering history

Into thick(er) air? Oxygen availability at humans’ physiological frontier on Mount Everest

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 VO2 max for 2°C warming since preindustrial. 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. </div

Precipitation characteristics and moisture source regions on Mt. Everest in the Khumbu, Nepal

Precipitation is critical to the water towers of the Hindu Kush-Himalaya-Karakoram region, exerting an important control on glacier mass balance and the water resources for 1.65 billion people. As hydroclimatic extremes and water stress have emerged as key hazards in the context of climate change, Nepal’s Khumbu region overlaps key vulnerabilities. Here we investigate the region’s precipitation characteristics and moisture sources through analysis of data from a new high-altitude network of automatic weather stations, which allow for a more complete understanding of the climatological precipitation data that are critical information for local communities in the Khumbu region, visitors, and downstream populations. Our findings demonstrate that the northern Bay of Bengal is potentially an important moisture source during the monsoon period (June to August) and that westerly trajectories over land predominate for precipitation events during the post-monsoon, winter, and pre-monsoon seasons

Direct observations of a Mt Everest snowstorm from the world’s highest surface-based radar observations

This paper details the world’s highest surface-based vertically pointing radar observations from Nepal’s Everest Base Camp during a snowstorm on 17 April 2019. The radar echo extended higher than the summit of Mt. Everest at times and indicated turbulence and environments favorable for riming. The observed precipitation and velocity structures are similar to those observed in other mountainous areas and suggest that satellite-based remote sensing of snowstorms can utilize assumptions of similar structures across a range of elevations

Weather on Mount Everest during the 2019 summer monsoon

Records from new high altitude weather stations reveal the meteorological conditions on Mt Everest during the 2019 monsoon. Using data from June-October, we show that the temperature, humidity, and winds announce the arrival of the monsoon, with changes that amplify with elevation. The largest change is therefore at the summit, where we estimate that monthly mean air temperature increased by 5.5 °C between June and July to average -19.1 °C over the monsoon. Such warming takes temperatures into the realm of winter conditions on much lower mountains of the mid-latitudes, illustrated with the well-known Mount Washington observatory (1,916 m; New Hampshire, USA). Although other dangers of climbing Everest may be enhanced during the monsoon, the cold induced hazard is much reduced

Going to Extremes: Installing the World’s Highest Weather Stations on Mount Everest

As the highest mountain on Earth, Mount Everest is an iconic peak that offers an unrivalled natural platform for measuring ongoing climate change across the full elevation range of Asia’s water towers. However, Everest’s extreme environment challenges data collection, particularly on the mountain’s upper slopes, where glaciers accumulate mass and mountaineers are most exposed. Weather stations have operated on Everest before, including the world’s previous highest, but coverage has been sparse in space and time. Here we describe the installation of a network of five automatic weather stations (AWSs), including the two highest stations on Earth (8,430 m.a.s.l and 7,945 m.a.s.l) which greatly improves monitoring of this iconic mountain. We highlight sample applications of the new data, including an initial assessment of surface energy fluxes at Camp II (6,464 m.a.s.l) and the South Col (7,945 m.a.s.l), which suggest melt occurs at both sites, despite persistently below-freezing air temperatures. This analysis indicates that melt may even be possible at the 8,850 m.a.s.l summit, and prompts a re-evaluation of empirical temperature index models used to simulate glacier melt in the Himalaya that focus only on air temperature. We also provide the first evaluation of numerical weather forecasts at almost 8,000 m.a.s.l and use of model output statistics to reduce forecast error, showcasing an important opportunity to improve climber safety on Everest. Looking forward, we emphasize the considerable potential of these freely available data for understanding weather and climate in the Himalaya and beyond, including tracking the behavior of upper-atmosphere winds, which the AWS network is uniquely positioned to monitor. </p