The incredible shrinking Denali!This week, Denali, the tallest peak in the United States, officially

The incredible shrinking Denali!This week, Denali, the tallest peak in the United States, officially shrank by 26 meters (83 feet), from 6,194 meters to 6,168 meters above sea level.Of course, the mountain itself didn’t change, only our measurements of it. Denali’s elevation was originally measured to be 20,320 feet in 1952 based on its properties in photographs. A 1989 field survey measured it to be 20,306 feet in height, but in many cases (including state documents) the 1952 estimate still seems to have been used. In those units, the officially acknowledged height now is 20,237 feet.In much of the United States, the most current topographic maps date back to the 1960’s and 1970’s, well before digital maps and satellite technologies became available. Some areas have been updated via satellites but the official topographic maps used by most government offices are the older ones, done with the best surveying technologies available at the time.So no, Denali isn’t really shrinking (just in case anyone is wondering, if it really shrank by 20+ meters over 25 years, that would put it on pace to vanish in less than 10,000 years, so no, it is not eroding or changing that quickly), our maps are just getting better. And just to note, it remains the tallest peak in North America.Starting in 2010, a partnership between the US Federal Government and Alaskan state government has been re-mapping Alaska with modern techniques including radar measurements; that mapping project produced this new height. Other new details have come out as well; an entire ridgeline of another mountain in Denali National Park, Mt. Dickey, was completely missing from the topographic maps and has now appeared.The goal is to finish the Alaskan project by 2016, but Alaska isn’t the only place that needs this treatment. Much of the U.S. needs re-mapped using modern techniques, and it’s not just for reasons of curiosity. Building permits, flood insurance, and geologic risk assessments for property and development benefit hugely from accurate maps, and the more accurate they are the more money is saved in the end.-JBBImage credit: Wikimedia Commonshttp://commons.wikimedia.org/wiki/File:Wonder_Lake,_Denali.jpgPress report:http://ltgov.alaska.gov/treadwell/press-room/full-press-release.html?pr=215Previous coverage of updating of maps:https://www.facebook.com/TheEarthStory/posts/531217026939346 -- source link

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