Wall Arch
Encyclopedia
Wall Arch was a natural sandstone arch
Natural arch
A natural arch or natural bridge is a natural geological formation where a rock arch forms, with an opening underneath. Most natural arches form as a narrow ridge, walled by cliffs, become narrower from erosion, with a softer rock stratum under the cliff-forming stratum gradually eroding out until...

 in the Arches National Park
Arches National Park
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....

 in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

. 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
Entrada Sandstone
The Entrada Sandstone is a formation in the San Rafael Group that is spread across the U.S. states of Wyoming, Colorado, northwest New Mexico, northeast Arizona and southeast Utah...

, 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
Devil's Garden
Devil's Garden is an area of Arches National Park, located near Moab, Utah, that features a series of rock fins that have broken out of the earth due to erosion and produce many spectacular views...

. No one observed the fall. It was the first collapse of a major arch in the park since sections of Landscape Arch
Landscape Arch
Landscape Arch is the longest of the many natural rock arches located in the Arches National Park in Utah, USA. The arch is among many in the area known as Devil's Garden in the north area of the park...

 fell in 1991. Officials from the National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...

 and Utah Geological Survey
Utah Geological Survey
The Utah Geological Survey is based in Salt Lake City, Utah, USA. It also has an office in Cedar City, Utah.It is a division of the Utah Department of Natural Resources and is an applied scientific agency, which creates, interprets, and provides information about Utah's geological environment,...

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.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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