View source for Devil's Slide (California)

{{Short description|Promontory in San Mateo County, California}}
{{Other places3|Devil's Slide (disambiguation)}}
{{Use mdy dates|date=October 2022}}
[[Image:Cliffs at devils slide california.jpg|thumb|right|300px|The sheer cliffs of the Devil's Slide promontory. A large area of slope failure is evident, marked by unweathered orange rocks and sharp truncations of vegetated areas.]]
'''Devil's Slide''' is a coastal [[promontory]] in [[California]], United States. It lies on the [[San Mateo County, California|San Mateo County]] coast between [[Pacifica, California|Pacifica]] and [[Montara, California|Montara]]. Its name comes from the rocky edges prone to accident.

==Natural setting==
Devil's Slide is a name given to a steep, rocky coastal [[promontory]] located about midway between [[Montara, California|Montara]] and the Linda Mar District of Pacifica. The terrain is characterized by steep, eroded slopes with natural gradients ranging between 30 and 50%. There are small coastal valleys throughout along the major drainages within the [[Montara Mountain]] watershed. The soils in these valleys are deep and moderately well-drained and have developed along the low terraces and alluvial fans of the stream channels.

The climate of the area is [[Mediterranean climate|Mediterranean]] with a strong maritime influence. The temperature range is narrow both seasonally and diurnally, while air moisture is relatively high.  Extremely dense [[northern coastal scrub]] covers most of the locale, especially over [[San Pedro Mountain]] and along the steeper foot slopes of Montara Mountain. Small grassy openings and barren rocky areas are scattered throughout the scrub areas. The inland area holds other types of vegetation including aquatic and coastal freshwater marshes/seeps, willow riparian scrub, coastal grassland, non-native forest, and pasture/ranch uses/non-native brushland. The [[endangered species]] [[Hickman's potentilla]] occurs on the slopes above [[Martini Creek]] at up to {{convert|430|ft|m|-1}}  elevation.

==Former State Route 1==
[[File:Devil's Slide (5212593737).jpg|thumb|Devil's Slide (far left) with the southern portal of the [[Tom Lantos Tunnels]] (far right) under construction in late 2010. Note the steeply eroded cliffs immediately above and below [[California State Route 1|Highway 1]].]]
Immediately east of Devil's Slide is a former stretch of [[California State Route 1]], famous for closures and [[landslide]]s, which also was called "Devil's Slide". Construction of the road began in 1935 and was completed in 1936, replacing the steep, narrow, and winding [[Pedro Mountain Road]]. It was known for landslides and [[erosion]] that often occur during winter storms, sometimes making the road impassable.

Devil's Slide was originally part of [[Ocean Shore Railroad]] that was proposed between San Francisco to Santa Cruz.<ref>{{Cite news |last=Meares |first=Hadley |date=2016-09-08 |title=Ghost Rail: The Brief, Troubled Life of the Ocean Shore Railroad |url=https://www.kcet.org/shows/california-coastal-trail/ghost-rail-the-brief-troubled-life-of-the-ocean-shore-railroad |access-date=2022-10-17 |work=KCET |language=en}}</ref>

The first major landslide destroyed much of the road in 1940. Another large slide in 1995 forced the road's closure for almost two years. In April 2006, the road began to develop large longitudinal cracks in the roadbed, indicating an imminent slide and forcing the highway's closure for five months as [[CalTrans]] worked to stabilize the slide.

On March 25, 2013, Caltrans shut down the landslide-prone coastal road, replacing it with the [[Tom Lantos Tunnels]], which take the highway through the promontory behind the precarious cliffs.<ref name=Mendoza>{{cite news|last=Mendoza|first=Martha|title=Cutting Edge Calif. Tunnels Poised to Open|url=https://abcnews.go.com/US/wireStory/cutting-edge-tunnels-poised-open-18581680 |work=ABC News |agency=[[Associated Press]]|accessdate=25 February 2013|date=24 February 2013}}</ref> On {{start date|2014|03|27}}, the {{convert|1.3|mi|km|adj=on}}-long [[Devil's Slide Trail]] was opened to pedestrians and bicyclists,<ref name=IsSafe>{{cite report |url=http://www.sanmateocourt.org/documents/grand_jury/2013/devilsslide.pdf |title=Is the New Devil's Slide Trail Safe? |author=San Mateo Grand Jury |date=8 July 2014 |publisher=Superior Court of California, County of San Mateo |accessdate=23 June 2016}}</ref> taking over the section of roadway formerly used by State Route 1 and now bypassed by the new tunnels.<ref>{{cite web |url=http://parks.smcgov.org/devils-slide-trail |title=Devil's Slide Trail |date=2016 |author=<!--Staff writer(s); no by-line.--> |website=County of San Mateo Parks Department |accessdate=23 June 2016}}</ref> The total cost to convert the highway into a trail was {{US$|1991525|2013|round=-3}}.<ref name=IsSafe />

==In popular culture==
Devil's Slide was used in a key scene of the 1960 thriller ''[[Portrait in Black]]'' with [[Lana Turner]] and [[Anthony Quinn]].  Turner and Quinn portrayed doomed lovers who deliberately pushed a car, containing the body of a murdered man, over the edge of the cliff.  The [[Universal Pictures|Universal]] crew obtained permission from the State of California to stage the scene, which involved retrieving the car from the bottom of the cliff once the scene had been successfully filmed.  The ''San Mateo Times'' printed a photograph of the filming of this sequence.<ref>American Movie Classics, ''San Mateo Times''</ref>

==Military history==
[[Image:Bunker at devils slide california.jpg|An exposed [[base end station]] at Devil's Slide|thumb]]
Devil's Slide was the location of a military triangulation station and observation site (known as Devil’s Bunker) used during [[World War II]] as part of the harbor defense of [[San Francisco]].  Prior to the advent of radar, military personnel used binoculars and compasses to search for ships at sea and relay their coordinates to a central post.  By combining information from multiple observation posts, a ship's precise location could be determined by [[triangulation]].  There were six military structures at the Devil's Slide: three concrete and steel observation pill-boxes, two concrete-and-earth bunkers, and a reinforced steel observation tower.  The pill-boxes were used as hardened observation posts, and one of the bunkers was used as a communications and command post.<ref>{{cite web |url=http://www.corpsfuds.org/reports/INPR/J09CA0789inpr.pdf |title=Site Survey Summary Sheet for DERP-F'UDS Site No.J09CAO78900: Devil's Slide |archiveurl=https://web.archive.org/web/20130113024710/http://www.corpsfuds.org/reports/INPR/J09CA0789inpr.pdf |publisher=Defense Environmental Restoration Program |date=August 26, 1991 |archivedate=January 13, 2013 }}</ref>  The southernmost bunker site was sold to a private owner in 1983, but some of the exposed structure remains.

==See also==
*[[Salinian Block]]
*[[Coastal erosion]]
*[[California landslides]]

==Bibliography==
* ''Biological Assessment, Species of Concern, Proposed Route 1 Devil's Slide Tunnel Bypass Project, San Mateo County, California'' Prepared by Caltrans, Office of Environmental Planning, South. July, 1998.
* Michael Hogan and Ballard George, ''Air Quality and Noise Analyses for the Bypass Alternative, Devil's Slide Improvement Project'', Caltrans District 4, prepared by Earth Metrics Inc., Burlingame, CA (1984)
* ''Devil's Slide Improvement Project, San Mateo County, California, Draft Second Supplemental Environmental Impact Statement'', Caltrans District 4 (1999)
* Hovland, John H., Ph.D., P.E., ''A Study of the Feasibility of Stabilizing the Landslide Area Along Highway One, San Mateo County, California, by Dewatering'', April, 1998
* Woodward-Clyde Consultants, ''Devil’s Slide Tunnel Study - Feasibility Report'', October, 1996.

==Footnotes==
{{Reflist}}

==External links==
{{commons category}}
{{wikisource|In Celebration of the Completion of the Bridges at Devil's Slide}}
* [http://www.coastal.ca.gov/ California Coastal Commission]
* [https://web.archive.org/web/20070928020204/http://www.greenfoothills.org/news/2001a/11-19-01_HMBReview.html Three-part series on the history of Devil's Slide]
* [https://www.flickr.com/photos/kqedquest/sets/72157600031882138/ KQED QUEST photo montage and article on tunnel]

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[[Category:Buildings and structures in San Mateo County, California]]
[[Category:Landforms of San Mateo County, California]]
[[Category:Roads in San Mateo County, California]]
[[Category:Coastal erosion in the United States]]
[[Category:California State Route 1]]
[[Category:Landslides in the United States]]
[[Category:CCT San Mateo Section 3]]