Mount Everest is 29,029 feet above sea level. Or, maybe it’s 29,017 feet. China and Nepal, which share the summit, have occasionally argued about the actual height of the mountain. Nepal has maintained the 29,029-foot mark since the 1950s. China claimed Everest has an actual rock height of 29,017 feet after a measurement in 2005 subtracted snow, while the traditional higher figure has always included the snowpack on the summit. Nepal and China agreed to agree on the 29,029-foot mark in 2010, possibly after more climbers wanted to approach from Nepal’s side because of the higher recognized elevation figure.
But now Nepal is conducting its own survey and plans to announce the results in January.
Past measurements have included scientists from around the world (those from Nepal have typically not been invited) but this time a two-person Nepali team, Chief Survey Officer Khim Lal Gautam and Survey Officer Rabin Karki, will climb Everest assisted by Sherpas, to take sophisticated GPS measurements from the top with a Trimble, a sort of wand familiar to anyone who has worked in any field that measures precise coordinates.
For ten minutes the two surveyors will stand on the peak and collect satellite data, providing about as close as a measurement as is possible. Then they will gather their gear and shuffle back to base camp to meet with fellow surveyors.
In addition to summit measurements, they’ll also take precise leveling, trigonometric leveling, gravity survey, and GNSS survey data into account to map the mountain’s height.
The Nepali government expects that the survey team will be able to pinpoint the height of Everest to within the centimeter.
Much of the heavy lifting of determining the precise height of the summit will come from ground-penetrating radar. It can beam through snow and bounce back from the rock closest to the summit to determine both the total height of the peak, including snowpack, and the rock below.
Put that data together with GPS readings from the summit, trigonometric calculations from the valley below, and take into account previous measurements, and, hopefully, that down-to-the-centimeter height will be nailed down.
Will it still be 29,029 feet? That measurement has been official since an Indian survey in 1954. Earthquakes may have shifted rock and snow since then, altering the height above sea level, and technology has certainly improved, potentially meaning a more accurate measurement. Other countries have tried to triangulate the height of Everest over the decades, occasionally producing a summit height taller or shorter than the officially recognized figure. The New York Times has a wonderful explanation of the history of Everest’s measurements, here.
We’ll all find out what the new, official height is January, 2020.