, Volume 5, Issue 3, pp 331–337 | Cite as

Ferguson rock slide buries California State Highway near Yosemite National Park

  • Edwin L. HarpEmail author
  • Mark E. Reid
  • Jonathan W. Godt
  • Jerome V. DeGraff
  • Alan J. Gallegos
Recent Landslides


During spring 2006, talus from the toe area of a rock-block slide of about 800,000 m3 buried California State Highway 140, one of the main routes into heavily-visited Yosemite National Park, USA. Closure of the highway for 92 days caused business losses of about 4.8 million USD. The rock slide, composed of slate and phyllite, moved slowly downslope from April to June 2006, creating a fresh head scarp with 9–12 m of displacement. Movement of the main rock slide, a re-activation of an older slide, was triggered by an exceptionally wet spring 2006, following a very wet spring 2005. As of autumn 2006, most of the main slide appeared to be at rest, although rocks occasionally continued to fall from steep, fractured rock masses at the toe area of the slide. Future behavior of the slide is difficult to predict, but possible scenarios range from continued scattered rock fall to complete rapid failure of the entire mass. Although unlikely except under very destabilizing circumstances, a worst-case, rapid failure of the entire rock slide could extend across the Merced River, damming the river and creating a reservoir. As a temporary measure, traffic has been rerouted to the opposite side of the Merced River at about the same elevation as the buried section of Highway 140. A state-of-the-art monitoring system has been installed to detect movement in the steep talus slope, movement of the main slide mass, local strong ground motion from regional earthquakes, and sudden changes in stream levels, possibly indicating damming of the river by slide material.


Rock slide Yosemite National Park Monitoring GPS data Hazard 


  1. Bateman PC, Krauskopf KB (1987) Geologic map of the El Portal Quadrangle, West-Central Sierra Nevada, California: U.S. Geological Survey Miscellaneous Field Studies Map MF-1998, Scale 1:62,500Google Scholar
  2. Bronson BR, Watters RJ (1987) The effects of long-term slope deformations on the stability of granitic rocks of the Sierra Nevada, Nevada, California. In: Proceedings of the Engineering Geology and Soils Engineering Symposium, 23rd: Utah State University Logan, p. 203–217Google Scholar
  3. Costa JE, Schuster RL (1991) Documented historical landslide dams from around the world. U.S. Geological survey. Open-File Rep 91–239:486Google Scholar
  4. Cronin VS (1992) Compound landslides: nature and hazard potential of secondary landslides within host landslides. In: Slosson JE, Keene AG, Johnson JA (eds) Landslides/landslide mitigation. vol. 9. Geological Society of America Reviews in Engineering Geology, Boulder, Colorado, pp 1–9Google Scholar
  5. DeGraff JV (2001) Sourgrass debris flow—a landslide triggered in the Sierra Nevada by the 1997 New Year Storm. In: Ferriz H, Anderson R (eds) Engineering Geology Practice in Northern California. vol. 12. California Division of Mines and Geology Bulletin 210/Association of Engineering Geologists Special Publication CA, pp 69–76Google Scholar
  6. Denlinger RP (2007) Simulations of potential runout and deposition of the Ferguson Rockslide, Merced River Canyon, California: U.S. Geol Sur Open-File Rep 2007–1275:23Google Scholar
  7. Fukuzono T (1990) Recent studies on time prediction of slope failure. Landslide News 4:9–12Google Scholar
  8. Gallegos AJ, DeGraff JV (2006) Ferguson rock slide geology report. U.S. Forest Service Report, 26Google Scholar
  9. Harp EL, Tanaka K, Sarmiento J, Keefer DK (1984) Landslides from the May 25–27, 1980, Mammoth Lakes, California earthquake sequence. U.S. Geological Survey Miscellaneous Investigations Series Map I-1612Google Scholar
  10. Huber NK, Bateman PC, Wahrhaftig C (1989) Geologic map of Yosemite National Park and vicinity, California. U.S. Geological Survey Miscellaneous Investigations Series Map I-1874, scale 1:125,000Google Scholar
  11. Kuehn MH, Bedrossian TL (1987) U.S. Highway 50 landslide near Whitehall, California. Calif Geol 40(11):247–255Google Scholar
  12. LaHusen RG (2005) Debris-flow instrumentation. In: Jakob M, Hungr O (eds) Debris-flow hazards and related phenomena. Praxis, Springer, Berlin, pp 291–304CrossRefGoogle Scholar
  13. LaHusen RG, Reid M E (2000) A versatile GPS system for monitoring deformation of active landslides and volcanoes. Eos, Transactions of the American Geophysical Union 81 (48) F320Google Scholar
  14. Morrissey MM, Wieczorek GF, Savage WZ (1999) Airblasts generated from rock-fall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park. J of Geophysical Research, B, Solid Earth and Planets 104(10):23189–23198CrossRefGoogle Scholar
  15. Reid ME, LaHusen R G, Ellis W L (1999) Real-time monitoring of active landslides. Fact Sheet—U. S. Geological Survey Report: FS 0091-99Google Scholar
  16. Sydnor RH (1997) Reconnaissance engineering geology of the Mill Creek Landslide of January 24, 1997. Calif Geol 50(3):74–83Google Scholar
  17. Terzaghi K (1950) Mechanism of landslides. In: Paige S (ed) Application of geology to engineering practice (Berkey Volume). Geological Society of America, New York, pp 83–123Google Scholar
  18. Varnes DJ (1983) Time-deformation relations in creep to failure of earth materials. Proceedings of the 7th Southeast Asian Geotechnical Conference 2:107–130Google Scholar
  19. Voight B (1989) A relation to describe rate-dependent material failure. Science 243:200–203CrossRefGoogle Scholar
  20. Wieczorek GF, Jager S (1996) Triggering mechanisms and depositional rates of postglacial slope-movement processes in the Yosemite Valley, California. Geomorphology 15:17–31CrossRefGoogle Scholar
  21. Wieczorek GF (2002) Catastrophic rockfalls and rockslides in the Sierra Nevada, USA. In: Evans SG, DeGraff JV (ed) Catastrophic landslides: effects, occurrence, and mechanisms. Geological Society of America Reviews in Engineering Geology XV, Boulder, Colorado, pp 165–190Google Scholar
  22. Wieczorek GF, Snyder JB, Waitt RB, Morrissey MM, Uhrhammer R, Harp EL, Norris RD, Bursik MI, Finewood LG (2000) The unusual air blast and dense sandy cloud triggered by the July 10, 1996, rock fall at Happy Isles, Yosemite National Park, California. Geol Soc Amer Bull 112(1):75–85CrossRefGoogle Scholar
  23. Wieczorek GF, Snyder JB, Alger CS, Isaacson KA (1992) Rock falls in Yosemite Valley, California. U.S. Geological Survey Open-File Report 92-387 38 p 2 appendices 4 plates 1 diskGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Edwin L. Harp
    • 1
    Email author
  • Mark E. Reid
    • 2
  • Jonathan W. Godt
    • 1
  • Jerome V. DeGraff
    • 3
  • Alan J. Gallegos
    • 3
  1. 1.U.S. Geological SurveyDenverUSA
  2. 2.U.S. Geological SurveyMenlo ParkUSA
  3. 3.U.S. Forest ServiceVallejoUSA

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