The Ferguson landslide, also commonly called the Ferguson Slide, is an active

landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...

in the Merced River canyon in

Mariposa County Mariposa County () is a county in the U.S. state of California. As of the 2020 U.S. Census, the population was 17,131. The county seat is Mariposa. It is located in the western foothills of the Sierra Nevada mountains, north of Fresno, east of ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, United States. In 2006, rocks and debris slid off Ferguson Ridge, blocking

California State Route 140 State Route 140 (SR 140) is a state highway in the U.S. state of California, 102 miles (164 km) in length. It begins in the San Joaquin Valley at Interstate 5 near Gustine, and runs east into Sierra Nevada, terminating in Yosemite National ...

, a primary access road to

Yosemite National Park Yosemite National Park ( ) is an American national park in California, surrounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an ar ...

. The slide still blocked the original road as of late 2021, although temporary bridges allow one-way traffic around the slide and into the park. The slide is a natural phenomenon, and resulted from the erosion dynamics of the river valley.

History

The slide began on April 29, 2006, and initially the highway remained open, with active monitoring and occasional temporary closures. By May 28, the road was closed permanently, stopping access to the park from Mariposa and severely impacting the local economy. Many park employees reside in Mariposa, and for several months a two-hour trip (one way) was required to get to work in the park. Revenue via the hospitality market dropped extensively, which included wages, profits to small business owners, and county government income from occupancy taxes. A

State of Emergency A state of emergency is a situation in which a government is empowered to be able to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. A government can declare such a state du ...

was declared in June 2006 for Mariposa County. FergusonSlideBridge-2014-01-10

Initially, two temporary bridges were built in August 2006. While this detour alleviated a significant portion of the economic impact to the area, vehicles over 28 feet could not use it. In June 2008, new temporary bridges which could accommodate longer vehicles were constructed. The detour via the bridges is one-way, controlled by traffic lights. At the height of the tourist season, this has sometimes resulted in significant delays. The temporary bridges access a road grade on the north side of the Merced River, which is a vestige of the

Yosemite Valley Railroad The Yosemite Valley Railroad (YVRR) was a short-line railroad operating from 1907 to 1945 in the state of California, mostly following the Merced River from Merced to Yosemite National Park, carrying a mixture of passenger and freight traffic. ...

. Repair of the highway was on permanent hold due to the encroachment of an endangered species into the slide area. In 2012, Assemblymember Kristin Olsen authored legislation that would allow the California Department of Fish and Game to do an initial take of the

Limestone Salamander The limestone salamander (''Hydromantes brunus'') is a member of the lungless salamander family. Discovered in 1952, this species belongs to a genus endemic to California. It is endemic to a portion of the Merced River Canyon in Mariposa County, ...

and place it in an Ecological Reserve. The legislation paved the way to restoring this important access route to Yosemite. Known officially as Assembly Bill No. 1973, it passed both houses of the California State Legislature and was signed into law by Gov. Governor Jerry Brown on July 13, 2012. After considering the option of a tunnel,

Caltrans The California Department of Transportation (Caltrans) is an Executive (government), executive department of the U.S. state of California. The department is part of the Government of California#State agencies, cabinet-level California State Tran ...

settled on a

rock shed A rock shed is a civil engineering structure used in mountainous areas where rock slides and land slides create highway closure problems. A rock shed is built over a roadway that is in the path of the slide. They are equally used to protect ra ...

design in 2014.

Ferguson Rock Shed

Caltrans plans to restore the original route of Highway 140 by building a protective rock shed, with construction split into two distinct projects: * Phase 1: Removing the existing talus material (approx. 147,000 tons) and installing cable drapery to minimize additional rock fall. Work began in early 2021. * Phase 2: Constructing a rock shed structure on the same alignment. Construction on the rock shed is expected to begin in Fall 2022 and last five years.

References

;Attributions * *

External links

* {{Coord, 37, 39, 24, N, 119, 54, 3, W, display=title, format=dms, type:event_region:US-CA Geological hazards Landslides in the United States Landslides in 2006 April 2006 events in the United States May 2006 events in the United States