Wall Arch was a natural sandstone arch in the Arches National Park in the U.S. state of Utah. Before its collapse in 2008, it was ranked 12th in size among the park's over 2,000 arches. At its largest, the opening underneath the span was 71 feet (22 m) wide by 33.5 feet (10 m) high. It consisted of Entrada Sandstone, specifically the member known as Slick Rock. Wall Arch was first reported and named in 1948 by Lewis T. McKinney.
Wall Arch collapsed sometime between the night of Monday, August 4, 2008, and the morning of August 5, temporarily blocking Devil's Garden Trail. No one observed the fall. It was the first collapse of a major arch in the park since sections of Landscape Arch fell in 1991. Officials from the National Park Service and Utah Geological Survey visited the site of the collapsed sandstone arch on Thursday, August 7, and noted stress fractures in the remaining formation which may cause additional collapse in the future.
Arches National Park is a U.S. National Park in eastern Utah. It is known for preserving over 2000 natural sandstone arches, including the world-famous Delicate Arch, in addition to a variety of unique geological resources and formations.
The park is located just outside of Moab, Utah, and is 76,679 acres (31,031 ha) in area. Its highest elevation is 5,653 feet (1,723 m) at Elephant Butte, and its lowest elevation is 4,085 feet (1,245 m) at the visitor center. Forty-three arches have collapsed due to erosion since 1970. The park receives 10 inches (250 mm) of rain a year on average.
Administered by the National Park Service, the area was originally created as a National Monument on April 12, 1929. It was redesignated as a National Park on November 12, 1971.