For Immediate Release

WASHINGTON—Scientists supported by the National Geographic and Boston’s Museum of Science were able to operate Global Positioning System satellite equipment on the very top of Mount Everest last May and have determined the precise height of the world’s tallest mountain: about seven feet higher than the current official elevation.

The revised elevation—29,035 feet (8,850 meters)—was announced November 11, 1999 by Bradford Washburn, renowned mountain photographer/explorer and honorary director of Boston’s Museum of Science, at the opening reception of the 87th annual meeting of the American Alpine Club. The event, held at National Geographic Society headquarters in Washington, D.C., was attended by a large number of America’s top Everest climbers and experts.

The National Geographic Society has accepted the new elevation for Everest and has just updated its flat wall map of the mountain. The change is noted on the Society’s “Mapmachine” Web site (www.nationalgeographic.com/mapmachine), and it will be included on all new globes and other cartographic products.

“National Geographic is accepting this new elevation for Everest because it is clearly the most authoritative and thoroughly executed measurement of the highest point on the Earth’s surface,” said Allen Carroll, the Society’s chief cartographer. “As always, National Geographic goes with the best sources.”

Everest’s new elevation is remarkably close to the previous official height of 29,028 feet (8,848 meters) set in 1954 by the Survey of India after picking the unweighted mean of altitudes determined from 12 different survey stations around the mountain. The observations made in 1954 varied by 17 feet (5 meters); the margin of error in the 1999 calculation was only a fraction of that.

Washburn said the latest data had been received “with enthusiastic approval” by the U.S. National Imagery and Mapping Agency and China’s National Bureau of Surveying and Mapping. “Our data for the altitude and position of Everest are based on precise observations made on May 5, 1999, for a total of 50 minutes,” Washburn said. This latest measurement stemmed from Washburn’s interest in 1995 to use lightweight Trimble GPS receivers, along with lithium batteries that work in temperatures as low as 40 below, to establish the highest bedrock survey station in the world on Everest’s 26,000-foot (7,930-meter) South Col. Then, running two receivers simultaneously, one at the South Col and the other at the summit, an extremely accurate altitude could be established for the top of the mountain.

With financial backing of the National Geographic Society’s Expeditions Council and Committee for Research and Exploration, Boston’s Museum of Science, Trimble Navigation and other donors, a team of nine made satellite observations at the summit of Everest.

Mountaineers Pete Athans and Bill Crouse reached the summit on May 5, 1999 with five Sherpas. “We climbed through the night so that we could be on top of the mountain to work in the warmest part of the day,” said Athans, a climber from the North Face Inc., who holds the record as the only Westerner who has reached Everest’s summit six times. “It was pleasant on top of the world that morning, just a little wind and 12°F below. The equipment worked without a problem.”

Ascending Everest is no small feat; more than 180 people have perished in the attempt. The GPS equipment was carried by two Sherpas in the team. Once in place at the very top of the mountain, it was able to receive signals from GPS satellites. Running in tandem with the receiver at 26,000 feet (7,930 meters) on the South Col, the receiver on the summit was able to give an exact altitude and position for the top of Everest.

Washburn said the reading of 29,035 feet (8,850 meters) showed no measurable change in the height of Everest calculated since GPS observations began at the South Col four years ago. But from GPS readings from the South Col over the past four years, with the receiver being attached to the same steel bolt fixed permanently into the rock face, it appears that the horizontal position of Everest seems to be moving steadily and slightly northeastward—between 6 centimeters (2.4 inches) a year. “At this moment, six months after we made our measurement, Everest is already almost certainly located slightly northeast of the position that it occupied in May,” he said. Washburn said that the figures could also change as the great fault system continues to shove India under Nepal and China, creating the Himalaya.

Calculating the revised elevation of Everest involved Roger Bilham of the University of Colorado, Boulder, two of his students, David Mencin and Frederick Blume, and Kristine Larson, of the aerospace engineering sciences department of the University of Colorado. Charles Corfield of Palo Alto, California, was the science manager of the last two Washburn expeditions to Everest. Also working closely with this team were two world leaders in the field of Himalayan geodesy: Muneendra Kumar of the National Imagery and Mapping Agency (NIMA) of the United States and Jun Yong Chen, Senior Advisor to the National Bureau of Surveying and Mapping of China.

A highlight planned for the reception on November 11 was a demonstration of technology developed by the MIT Media Lab to call up by satellite telephone a new, permanent monitoring station at Everest’s 26,000-foot (7,930-meter) South Col for a report on the weather at that moment. Washburn, 89, is an honorary member of the American Alpine Club. He began his mountaineering career in his teens, climbing the loftiest Alps. In 1935 he led a National Geographic Society-sponsored expedition that recorded 6,000 square miles of Canada’s Yukon Territory, an area previously blank on the world’s maps. With his wife, Barbara, in cooperation with the Society and Swissair Photo Surveys of Zurich, he produced in 1988 the most detailed and accurate map ever made of Mount Everest, which the National Geographic Society sent to 11 million members worldwide. That topographic wall map, updated to reflect the revised elevation of the world’s tallest mountain, may be ordered for U.S.$13.95 by calling 800 962 1643.

For dispatches from the expedition to revise Everest’s elevation, visit the Society’s Web site—www.nationalgeographic.com/everest. You can also learn more at www.ngnews.com/news/1999/11/111299/everest_7303.asp

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