Things Are Looking Up for Denver, Rocky Mountains

The Mile High City nickname comes up a little short these days.

The U.S. Geodetic Survey’s newest calculations show that some parts of the city, including the state capitol, are 3 feet higher than reputation would have it. But geologists stressed that doesn’t mean that Denver needs to change its famous nickname, and the mayor’s office said there are no plans to do so.

“The Mile High City is kind of a signature name for Denver, and I think that will always remain,” said Andrew Hudson, spokesman for Mayor Wellington Webb. “It sounds sort of unreasonable to say the mile-high-plus-3-feet city.”

Reflecting cartographic accuracy more than geologic uplifting, the new calculations set the official heights of many Colorado landmarks and the central Rockies as much as 7 feet higher than previously thought.

The changes weren’t big enough to shake up the rankings of any of the state’s 54 14,000-foot peaks or create any new 14ers.

Pikes Peak west of Colorado Springs gained 5 feet to 14,115 feet, while Longs Peak in north-central Colorado gained 4 feet. The state’s highest point, Mt. Elbert near Leadville, gained 7 feet to make it 14,440 feet above sea level.

Other areas of the country also changed, but some of the biggest differences were found in the central Rockies, where the range’s strong gravitational pull has thrown off instruments used to measure elevation since the days of the Hayden survey in the 19th century.

In Wyoming, Grand Teton in Grand Teton National Park increased 5 feet to 13,775 feet above sea level. Franc’s Peak in the bordering Shoshone National Forest grew by 6 feet to 13,164 feet.

The highest point in Montana, Granite Peak, also jumped 6 feet to 12,807 feet, while Wheeler Peak in northern New Mexico is now 13,167 feet, about 5 feet higher than previously thought.

“It isn’t that the old surveys are wrong; it just means we have a new starting point,” said Jack Reed, geologist with the U.S. Geological Survey. “It doesn’t necessarily mean the mountains are getting bigger.”

The revisions actually came about in the 1990s, when Congress formally adopted the National Geodetic Vertical Datum of 1988, but are just now starting to show up on maps.

Number-crunchers at the U.S. Geodetic Survey used thousands of benchmarks created since the last comprehensive survey in 1929 to recalculate what is known as the geoid, an imaginary surface used to measure elevation that represents sea level.

Geologists also used satellite data that shows, within millimeters, where the center of the earth’s gravity lies, said Richard Cohen, Colorado’s advisor to the U.S. Geodetic Survey.

“Some parts of the United States changed a little bit, while some parts changed a lot,” he said. “Of course, we have a lot of elevation here, so our numbers changed quite a bit.”

Colorado’s elevation rose an average of 3 feet. Changes in flatter areas of the country, such as the Midwest and East Coast, measured less than a foot, Cohen said.

“Basically, where things are flat, it doesn’t make much of a difference,” Reed said.

In Denver, a team of surveyors will spend a weekend running levels from four geographic benchmarks surrounding the capitol to install the capitol’s new mile-high marker, probably next spring, said Herbert W. Stoughton, a surveyor who heads Metro State College of Denver’s surveying and mapping program.

“Every observation we read, we read to a tenth of a millimeter.... It takes very precise, very specialized equipment to do this,” he said.

Two markers, one a brass cap and one an inscription, already line the steps claiming to mark the spot where the capitol sits one mile above sea level.

The inscription, which reads “One Mile Above Sea Level,” was carved into the steps in 1947 after repeated thefts of a brass plaque at the top of the steps, according to state archives.

New measurements by a group of Colorado State University engineering students in 1969 prompted installation of the brass cap three steps higher. The new marker will likely sit a few steps higher than that.

So how can capitol visitors make sure they’re standing exactly one mile above sea level?

“My suggestion is you should lay across about six steps,” said Dan Hopkins, spokesman for Gov. Bill Owens.