SALT LAKE CITY (AP) — Rangers at Utah's Arches National Park were investigating large graffiti Thursday that was carved so deeply into a famous red rock arch that it might be impossible to erase, officials said. The carvings discovered earlier this month measure about 4 feet across and 3 feet high, park Superintendent Kate Cannon said. The vandalism is part of a "tidal wave of graffiti" at Arches and other national parks in recent years, she said. Two years ago, at least eight national parks in the West began the delicate task of cleaning up graffiti-like paintings left on famous, picturesque landscapes.Read more on NewsOK.com