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.
A mass-movement involving the downslope transport, under gravitational influence, of soil and rock materials.
The relatively free falling or precipitous movement of rock from a slope by rolling, falling, toppling, and/or bouncing.
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.
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.
November 2017, Spring Creek Road Landslide, Riverdale
1990s to 2016, Springhill 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
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 – 2004, Wildfires 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