This is the first installment in a multi-part series by Jeffrey Yates. Yates tells how eight men determinedly climbed Alaska’s Mount McKinley to be the first to survey McKinley’s height with GPS technology and install a permanent bench mark. It was originally published in Lasting Impressions.
Why do people climb mountains? Certainly the thrill motivates most, but for others there are more practical reasons to take such risks. For surveyors, there are scientific and professional reasons.
The eight-member climbing team of the June 1989 Mount McKinley Global Positioning System (GPS) Expedition made its way to the summit of North America’s tallest mountain, in south central Alaska, for two reasons: to determine the deflection of vertical near a mountain mass like McKinley, and to demonstrate that the technology is now available to measure precisely in remote, high-altitude environments.
Mount McKinley—called Denali, “The Great One,” by natives—is possibly the largest massif in the world, since it rises from near sea level. When viewed from Anchorage, Alaska, McKinley seems to stand alone. In comparison, Mount Everest gets a “head start” because it rises from a 14,000-foot plateau in the Himalayas.
And McKinley is considered to be one of the coldest mountains on Earth. Even in June, ambient air temperatures can fall to -40◦ F. Windstorms can last a week or more with wind velocities sometimes exceeding 100 miles per hour, enough to freeze exposed skin in literally seconds. Blizzards last for days, dropping as much as three feet of new snow per day. These weather extremes are due to the low barometric pressures of this high latitude.
While only a byproduct of the expedition, the GPS measurement of Mount McKinley’s summit elevation may produce one of the more profound results. Dr. Bradford Washburn, honorary director at the Boston Museum of Science, in conjunction with Commander Howard Cole of the U.S. Coast and Geodetic Survey, measured Mount McKinley’s summit in 1953; his figure of 20,320 feet was verified in 1977. Members of the 1989 expedition kept in contact with Washburn, who made recommendations regarding which bench marks to use to compare with his 1953 measurements. Making ties to the stations used by Washburn during his survey was scheduled for the summer of 1990.
The notion of a Mount McKinley GPS expedition was sparked by a 1986 controversy surrounding satellite measurements of K2, the world’s second tallest peak—for awhile it looked as if it might, in fact, be the world’s tallest peak. Further satellite measurements allowed Mount Everest to retain its title, but questions remained regarding the use of satellite technology to determine the heights of major peaks around the world.
Ron Cothren, L.S., assistant professor of Engineering at the University of Alaska, Anchorage (UAA), accepted a challenge made at the 1987 Alaska Society of Professional Surveyors Surveying and Mapping Conference and became the project’s coordinator. Jeff Yates, a photogrammetrist at AeroMap U.S. Inc., in Anchorage, signed on as assistant project coordinator.
Join us next month for another installment in Mount McKinley . . . Just a Hike Up The Mountain.
Originally published in Lasting Impressions by Rhonda Rushing.
Published in Caching Now, August, 2009