From Everest to Aconcagua: Instrument Innovation Across Continents

By Ellen Estabrook

On February 18, 2025, a team of climbers and scientists summited Aconcagua – the highest mountain in the western and southern hemisphere – and installed a weather station a few meters from the top, at 22,769 feet, or 6,940 meters above sea level.

Climatologist, professor, and National Geographic Explorer Dr. Baker Perry co-led the expedition with a Mount Washington Observatory (MWOBS) pitot anemometer—and other instruments supplied by partners—in tow. The goal: to deploy five observation sites on the mountain to better understand  water availability in the Andes Centrales, a region critically impacted by a 15-year mega-drought.

This project comes just three years after the team’s expedition on Mount Everest, the first successful use case of a modified MWOBS pitot being installed at altitudes exceeding Mount Washington’s summit. Two of the MWOBS anemometers were installed at Everest Camp IV and Bishop Rock (~7,925 meters and 8,830 meters, respectively). Moreover, the Everest network comprises the highest weather station on Earth.

When MWOBS Director of Technology Keith Garrett was approached by Baker Perry to supply another unit for Argentina’s Aconcagua, there was no hesitation. For efficiency regarding the machining process, one additional unit and extra parts were manufactured for testing and repair purposes during the Mount Everest expedition. The unit now installed on Aconcagua had just returned from a year of deployment at Camp IV on Mount Everest. 

“Our summit pitot systems are extremely large and heavy. A unit needed to be constructed that would not only be convenient to pack into these remote locations, but also survive the anticipated extreme conditions,” Garrett said. 

A pitot system, he continued, is fairly straightforward, consisting of a pitot tube and a differential pressure transducer enclosed in an extremely robust housing, relying on measurements of temperature, relative humidity, and pressure to complete the calculations necessary to determine wind speed.

“The housing needed to be simple to machine due to time constraints (its “can-like” aesthetic). It needed to have built-in mounts capable of several variations of installation, and be as simple as possible. It only requires four wingnuts to be tightened for installation,” Garrett said, again highlighting the simplicity of installation being a key factor given the extremes of their deployed locations.  

Garrett turned to his team to help with production, including Brett Williams of Wolfeboro, who did the 3D drawings/CAD work, and Hanson Precision Machine of Tamworth, who manufactured the enclosures. The pitot tube itself was a customized design sourced from a Virginia based aerospace contractor.

“The next iteration of these units should weigh less than 2.5kg each, and be able to vane with the wind, both features which are difficult to employ due to the technology of a pressure transducer,” Garrett explained. “Our first completely wireless tests have been successful, however add cost, complexity, and a multitude of failure points which I would love to avoid, with lightning being a major concern.”

The custom pitot units are fixed-direction, with a directional window of about +- 20 degrees from their orientation, and are aimed into the prevailing winds, meaning they capture wind blowing within a narrow range of the fixed direction.

They record wind speed and the raw sensor output used to calculate the wind speed.

The pitot complements a suite of many instruments built to withstand the extremes of these alpine locales. Wind, temperature, humidity,  solar radiation, air pressure, and precipitation along with other measurements are being recorded continuously.

Information collected by these stations is integrated into a global network for scientists to use, transmitted via the NOAA GOES satellite constellation and ingested directly by NOAA DCS (Data Collection System). The data collected from Aconcagua and other sites will aid in better understanding factors shaping the world’s high altitude glaciers and weather patterns over time.

“We really have not had observations from these elevations in the Andes, and this is a huge opportunity to expand our knowledge, our observational networks, into this critical part of the world,” Perry said.

Changes in temperature and precipitation in the Andes Centrales are noted as two key variables for water availability in the region: “The Aconcagua weather stations will provide critical data to understand the hydrological cycle in this important water tower that sustains the Mendoza River and millions of people downstream,” Perry said.

Overall implications of the research are far-reaching, not only relaying real-time information on the changing climate of the Andes Mountains, but also improving hiker safety for the thousands recreating there with improved forecasts (an estimated 3,000 climbers attempt Aconcagua each year).

Alongside key partners, MWOBS is helping scientists understand high alpine and extreme environments on a global scale through instrument innovation.

“Having something that is a direct product of Mount Washington Observatory deployed on two different continents, on two of the Seven Summits, is beyond words,” Garrett said.

Project Wayra, (“Wayra” means “wind” in Quechua, an Andean Indigenous language), is a collaboration between Argentina and the United States, with support from numerous partners including the National Aeronautics and Space Administration (NASA), INKA Expeditions, National Geographic, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA), among others.

Along with MWOBS’s pitot anemometer, equipment was also provided by Campbell Scientific, OTT HydroMet, RM Young, and Lightning Master.

Pierre Pitte, glaciologist, expedition co-lead, and IANIGLA researcher, said of the project: “[It] is a unique opportunity that has allowed us to bring together agencies and universities from different countries, and it shows that by joining forces, we can achieve incredible things, such as equipping the highest peak in America—a challenge that had never been accomplished.”

Pitte continued: “It would have been impossible for us to accomplish what we did without a strong international collaboration, especially in this very complex moment for science.”

View the full press release here.