GEOLOGIC HAZARDS

Landslide Hazards

Landslides are common natural hazards in Utah that often occur without warning and can result in destructive, costly outcomes. They can be naturally occurring or human-caused. Many Utah landslides are considered dormant, but recent slope failures are commonly reactivations of pre-existing landslides, suggesting that even so-called dormant landslides may continue to exhibit slow creep or are capable of renewed movement if stability thresholds are exceeded. Steep slopes, mountainous terrain, rock types, and narrow, debris-choked canyons all contribute to our region’s susceptibility to landslide hazards. Various types of landslides in Utah are debris flows, slides, and rockfalls.

Slide and Debris Avalanche Hazards

A mass-movement involving the downslope transport, under gravitational influence, of soil and rock materials.

Rockfalls

The relatively free falling or precipitous movement of rock from a slope by rolling, falling, toppling, and/or bouncing.
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Debris Flows

A slurry of rock, soil, organic matter, and water that flows down channels and onto alluvial fans and can travel long distances very quickly.
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Generalized landslide map.

Costs of Landslide Hazards

Landslides have caused significant economic loss in Utah. Damaged or destroyed buildings, roadways, and railroads (also blocked rivers causing destructive flooding) from landslides have not only resulted in economic loss, but also loss of life. There have been several notable landslide events throughout the state. Many of these events have occurred at or near developed areas where appropriate mitigation measures could have been employed. Landslide-hazard maps are available to provide consultants, local governments, and the public a better understanding of Utah’s landslide hazard.

Reducing the Risk

Recognition of landslide risk prior to development and implementation of appropriate land-use planning and landslide mitigation measures are the most effective means to reduce risk. Many hillslopes are prone to landsliding, particularly where development has taken place on existing landslides or where grading has modified a slope and reduced its stability. In Utah, nearly all recent landslides have occurred as reactivations of pre-existing landslides. Therefore, historical landslides, prehistoric landslides, and steep slopes prone to landsliding must be thoroughly investigated prior to development activities, along with regional groundwater and landscape and other irrigation activities.

Headscarp undercutting the garage of one of the evacuated homes in Riverdale City, October 23, 2018. Photo by Ben Erickson.

When considering development on a hillslope or adjacent area property, owners should consult with local planning and building officials, nearby property owners, and geotechnical consultants knowledgeable about previous landslides and local landslide susceptibility before building in these areas. The Utah Geological Survey (UGS) recommends site-specific geologic hazard and geotechnical investigations for all new development. If landslide hazards are present, the professionals should disclose the hazards and provide appropriate recommendations for grading, groundwater control, project design, and construction that will reduce the hazards.

Excessive irrigation can easily cause a neighbor near or on a slope to lose their home from a landslide by elevating the groundwater table. The use of very-low water xeriscape landscaping and/or smart irrigation controllers that adjust the amount of water applied to landscapes based on weather, plant/turf, and soil data, can significantly reduce the amount of excess water that percolates through the soil as groundwater and save money.

Various rebates are available from Utah’s water conservancy districts for smart irrigation controllers and other water-saving devices for landscape irrigation that reduce water use and save you money.

Landslide Events

November 2017, Spring Creek Road Landslide, Riverdale

1990s to 2016Springhill Landslide, North Salt Lake

August 5, 2014, Parkway Drive Landslide, North Salt Lake

December 12, 2013, Fatal Rock Fall, Rockville

2011 Landslides in Utah

February 10, 2010, Rock Fall in Rockville, Washington County

April 11, 2009, Rock Fall in Provo, Utah County

2009 Northern Utah Landslides

2006 Northern Utah Landslides

2005-2006 Creekside Drive Landslides, Mountain Green

April 15, 2006, Sunset Drive Landslide, Layton

April 9, 2006, South Weber Landslide, South Weber

May 12, 2005, Rock Fall in Provo, Utah County

April 28, 2005, Sage Vista Lane Landslide, Cedar Hills

March 2005, East Lawn Memorial Hills Cemetery Landslides, Provo

March 12, 2005, Kanab Creek Landslide, Kane County

February 20, 2005, South Weber Landslide, South Weber

2000 – 2004Wildfires and Debris Flows in Northern Utah

July 26, 2004, Debris Flows near Spring Lake & Santaquin, Utah County

April 9, 2004, East Capitol Boulevard–City Creek Landslide

April 6, 2004, Debris Flows in Farmington, Davis County

March 22, 2004, Rock Fall near Devils Slide, Morgan County

September 2002, Spring Lake & Santaquin debris flow photos, Utah County

February 2001, Frontier Drive Landslide, Mountain Green

2001 Heather Drive Landslide, Layton

Preliminary Landslide History Database of Utah, 1850-1978

Landslide Publications and Maps

Report of Investigation #271

Reconnaissance of Landslides and Preliminary Landslide Hazard Assessment Along a Portion of Browns Park Road, Daggett County, Utah

Special Study #164

Landslide inventory map of Seely Creek and Big Bear Creek drainages, Sanpete and Emery Counties, Utah

Special Study #161

Landslide Inventory Map of the Ferron Creek Area, Sanpete and Emery Counties, Utah

Map #273

Landslide Inventory Map of the Sixmile Canyon and North Hollow Area, Sanpete County, Utah

View All Hazard Publications


Landslide Articles

Search:
TitleTopicPublished
The Curious Spring Creek Road Landslide Landslides 2019
2017 Flooding And Landslides In Box Elder County, Utah Hazards 2017
Update on the Markagunt gravity slide: Utah’s largest landslide just got bigger – a lot bigger Geologic History 2016
Bingham Canyon’s Manefay Landslides and the Future of the Mine Mining 2016
What geologic hazards should I be aware of as a homeowner in Utah? Hazards 2016
The Early Miocene Markagunt Megabreccia: Utah’s Largest Catastrophic Landslide Geologic History 2013
Another large landslide closes highway near Cedar City, Utah Hazards 2012
2011 Landslides in Utah Hazards 2012
Landslide Hazards in Utah Hazards 2011
Updated Landslide Maps of Utah Maps 2011
GPS Monitoring of Slow-Moving Landslides Hazards 2011
Ancient Landslides of the Beaver Dam Mountains, Washington County, Utah Geologic History 2009
Landslide Inventory Mapping in Twelvemile Canyon, Central Utah Hazards 2009
Logan Landslide Hazards 2009
The Green Pond Landslide, Imperceptibly Moving Ground Hazards 2008
Putting down roots in earthquake country – your handbook for earthquakes in Utah, Utah Seismic Safety Commission (pdf) Earthquakes 2008
The 2001 Heather Drive Landslide, Layton, Davis County, Utah Hazards 2007
The 2005 Sage Vista Lane Landslide, Cedar Hills, Utah County, Utah Hazards 2007
The 2005-06 Creekside Drive Area Landslides, Mountain Green, Morgan County, Utah Hazards 2007
2006 Landslides Hazards 2007
Protecting Utah Homes Hazards 2005
Landslides keep Hazards Program busy Hazards 2005
Thistle Landslide Revisited, Utah County Hazards 2005
Landslide damaged six Layton homes Hazards 2002
Massive Gravity Slides Show the Value of Detailed Mapping Maps 2002
Landslides: What they are, why they occur Hazards 2001
Homeowner's Guide to Recognizing and Reducing Landslide Damage on their Property Hazards 1998
Stability of the Pine Ridge Landslide at Timber Lakes Estates, Wasatch County, Utah: Implications for Future Development and Land-Use Planning Hazards 1997
Landslide evaluation issues– examples from Timber Lakes Estates Landslides 1997

Landslide Articles: 29

External Links

Utah Landslide Database

Contains current, detailed (1:12,000 or 1:24,000-scale) landslide inventory mapping showing landslide boundaries and their source areas, along with extensive landslide characteristic descriptions, and a legacy compilation of existing landslide boundaries, scarps, and debris flow paths (1:24,000 to 1:500,000-scale) from a variety of map sources.