The world’s highest weather station went offline in 2020. Now, an upgraded version has been deployed on the roof of the world.
Members of the expedition led by the National Geographic Society are installing a new weather station near the summit of Mount Everest. Its data will open a scientific window to a range of topics, from glacier melt to changing crop cycles.
On a picturesque day in 2021, Tenzing Gyalzen Sherpa stood atop the Balcony, a windswept resting spot high on the southeast ridge of Everest. In front of his crampons, partially buried in the hardened snow, lay the remnants of the world’s highest weather station.
When the station was first set up and bolted to the rock, it resembled an elaborate garden antenna adorned with bird feeders and wind vanes. In reality, it was $30,000 worth of precision instruments designed to measure wind, humidity, temperature, solar radiation, and barometric pressure. Now, the toppled two-meter-tall mast lay on its side, embedded in the ice.
Tenzing, a 31-year-old electrician and mountain guide, pulled out his phone from his down suit and began taking pictures of the scene. The Balcony station had ceased transmitting on January 20, 2020, seven months after its installation. It was one of five automatic weather stations placed in May 2019 as part of a collaboration between the National Geographic Society, Tribhuvan University in Kathmandu, and the government of Nepal, with funding from Rolex.
Kneeling in the snow beside the shattered station, Tenzing took out a screwdriver and a wrench from his backpack and began loosening a small gray Pelican case that was bolted to the mast. Inside was a data logger containing the last data the station had collected before succumbing to the extreme conditions.
The team brought a redesigned weather station to replace the one installed in 2019. They placed the new station at a higher point on the mountain, known as Bishop Rock, a member of the 1963 expedition, which was the first American team to reach the summit of Everest.
For climatologists Tom Matthews and Baker Perry, co-directors of the project, the readings transmitted by the station via satellite link have provided a treasure trove of knowledge about the “hidden realm” of weather on the world’s highest mountain and the surrounding Hindu Kush Himalaya. As they analyze the data from 2019 and 2020, surprising conclusions are emerging in various fields of study, from human physiology to long-term water supply and seasonal crop cycles.
In particular, the stations have revealed that high-altitude snow and ice were disappearing much faster than previously assumed.
“The summit of Everest may be the sunniest place on Earth,” says Matthews. When all that energy is reflected or absorbed on the mountain’s surface, it directly transforms solid ice into vapor, resulting in significant ice mass loss, even at temperatures far below freezing.
“Effectively, more melting is happening at high altitude than we knew, affecting our estimates of the amount of snow present,” explains Matthews. “And that can have implications for estimates of glacier sensitivity to temperature change.”
From the data collected by the weather stations, the team also gained new insights relevant to the hundreds of climbers who visit Everest each year. For example, Matthews discovered that the amount of oxygen available to climbers on the upper slopes varies significantly with the weather.
Collectively, the network was gathering information that could directly impact not only the lives of climbers and sherpas but also the lives of the 1.6 billion people who depend on the region’s freshwater—until its components started to fail.
Around the same time that the Balcony station stopped transmitting, the wind sensors located below it (at the next highest station, the South Col) also disconnected. “We saw a gust of about 240 kilometers per hour just before, so there’s no doubt about what happened,” says Matthews.
The team members divided the disassembled pieces of the weather station among themselves to carry them up to the summit.
But before they could repair the technology, COVID halted all activity on the south face of Everest in 2020. So it wasn’t until last year that Tenzing and another Sherpa could finally visit the Everest network for its first official maintenance.
At the lower stations, they installed new sensors, replaced batteries, and inspected accessories and bolts. Then, Tenzing climbed up to the Balcony station to assess the damage and retrieve its data logger.
But it wasn’t over. The team was already planning the replacement of the damaged equipment, an upgraded weather station, and Tenzing needed to scout a higher location for it. He continued ascending to Bishop Rock, a landmark named after Barry Bishop, a member of the first American expedition to summit Everest in 1963. At 8,810 meters, it’s about 50 vertical meters below the summit and is the planned location for the new, highest weather station.
Weather station testing laboratory
The term “automated weather station” is somewhat misleading, as every weather station must be regularly maintained by human technicians. Against the elements, any moving part will eventually fail.
Keith Garrett can attest to this. As the Chief Technology Officer of the Mount Washington Observatory in New Hampshire, USA, Garrett maintains a network of 18 automated weather stations in the White Mountains. Located in the path of three major storm tracks and about 160 kilometers from the North Atlantic, Mount Washington regularly records winds exceeding 160 kilometers per hour for over 100 days a year.
“We will see temperature sensors ripped out, with the radiation shield destroyed,” says Garrett. “I’m trying to think of something that hasn’t broken.”
All of this made Mount Washington an ideal testing ground for the team building version two of the Everest weather stations.
Tenzing Gyalzen Sherpa took photos of the destroyed weather station installed in 2019.
The station transmitted its last data on January 20, 2020, seven months after its installation. Eventually, all the pieces of the destroyed station will be removed from the mountain.
In addition to replacing the highest weather station, the team performed maintenance on the other four automated weather stations located further down the mountain.
The violent winds were a key factor that the Everest engineering team had to consider. One advantage of placing a weather station near the summit of the mountain is that it can measure the bottom of the jet stream, but that also means the wind sensors must be able to withstand sustained periods of hurricane-force winds.
Yet wind sensors on a station are often among its most vulnerable instruments. “Propeller anemometers require regular maintenance. Bearings wear out, the assembly can fail, and the propellers break, especially when there’s a lot of ice,” says Garrett.
The least problematic wind sensor by far is the Pitot tube anemometer, a device invented in the 18th century by French engineer Henri Pitot. Today, its modern iterations are ubiquitous in the aviation industry in the form of narrow metal tubes protruding from aircraft wings and noses.
“The advantage of the Pitot sensor is that it has no moving parts,” explains Baker Perry. But it also has a drawback: the sensor can only monitor wind from a 40-degree width in a fixed direction and must be oriented toward the prevailing wind. And because everything has to be hand-carried to the mountain, weight is a significant concern. So, working in collaboration with the National Geographic team, Garrett drastically downsized the existing Pitot technology, reducing a 19-kilogram system to less than two.
After a winter of testing at the summit of Mount Washington, the new sensor seemed viable. It just needed to be brought to the roof of the world and installed.
Base Camp 2 was the first stop for the climbers on their way to the upper parts of the mountain.
This spring, Tenzing, Perry, and Matthews returned to Everest. They were accompanied by 12 other sherpas, most of whom had participated in the original weather station expedition. The team gathered at the base camp, along with hundreds of mountaineers and recreational guides who had come together for the main climbing season of 2022.
The new weather station they brought to install on Bishop Rock included several improved components, including Garrett’s ultralight Pitot tube wind sensor design. Their plan was to remove the destroyed station at the Balcony and mount the new one in the location Bishop Rock that Tenzing had explored the previous year.
It wouldn’t be a small effort or without risks, but Tenzing and all the sherpas working on the mountain recognized that the weather stations provided several direct benefits. Weather data is essential for any high mountain climb, helping guides plan expeditions and maintain the safety of clients. Furthermore, if things go wrong and a climber needs to be rescued, providing real-time data to helicopter pilots and rescuers exponentially increases the chances of success. Tenzing put it simply: “We save more climbers’ lives.”
On the morning of May 9th, the team members began to arrive at Bishop Rock at 9 a.m. The wind was blowing over Everest at 64 kilometers per hour, making the wind chill feel like 40 degrees below zero. Perry began to feel unwell and had to return to base camp.
To secure the weather station to the mountain, the Sherpas used battery-powered drills to screw the tripod into the rock.
When the team began installing the new weather station, Matthews realized that his right hand fingers were wooden from the freezing cold; he couldn’t provide any real assistance. But the Sherpa guides had been preparing for this moment since 2019. Eight team members each carried a 24-volt battery in their down suits to keep them warm for drilling the basic anchor bolts.
In the biting, gusty air, the successful installation took them around two and a half hours, an hour longer than the team had expected. As they worked, a long line of mountaineers and their guides were approaching the summit while Tenzing completed the final wiring to power the station.
When Tenzing, Matthews, and their fellow Sherpas returned to the base camp several hours later, the new station was already transmitting data. “We have a good chance of measuring wind for a full winter,” Matthews reflects. “That would be fascinating.”
Meanwhile, news had emerged that a team of Chinese scientists had installed their own network of seven weather stations on Everest. It was on the north face of the mountain, the opposite side from the climb led by Tenzing, Matthews, and Baker. And the elevation of the highest station in the Chinese network? It is reported to be roughly the same elevation as Bishop Rock. Just a stone’s throw from the summit.
Does this mean there is a new international race to put weather stations on the world’s highest mountain? Matthews downplays that kind of debate. “I think more information from Everest is much better for everyone,” he says.
