by Francis Ashland

An upslope-facing scarp in the Springhill landslide in North Salt Lake. Additional damage to several of the houses on the landslide has resulted from an increase in the rate of movement in 2009.

Local wet conditions in northern Utah have caused some landslides to reactivate along with other types of shallow slope failures. Areas with active landslides in early 2009 include Ogden Valley in eastern Weber County, western Morgan County, southeastern Davis County, and Spanish Fork Canyon in Utah County. Examples include:

1. reactivation or acceleration of persistently moving historical landslides,
2. minor movement of landslides in highway cut slopes,
3. local highway embankment and rock-wall failures, and
4. local shallow slides on steep slopes in pre-existing landslides.

Damaging Landslide Movement

Above-normal precipitation in southeastern Davis County has caused an increase in the rate of movement of the Springhill landslide in North Salt Lake, resulting in additional damage to houses, roads, and buried utilities. The landslide has moved persistently since the late 1990s, severely damaging three houses since 1998.

Head and left side of a shallow snowmelt-induced landslide in fill in the front yard of a house in the Ogden Valley area.

By early 2009, the landslide was moving at a yearly rate of about 20 inches per year. Click here for additional information on the Springhill landslide.

Damaging landsliding has also occurred in Ogden Valley and the Snowbasin area of eastern Weber County. Snowmelt-induced landsliding occurred in the front yard of a house in the foothills of Ogden Valley, where saturated fill soil slid onto a driveway that crossed the slope.

Reactivation of pre-existing landslides crossed by State Route 226 (near Snowbasin ski resort) is causing minor damage to the highway in several locations. In addition, embankment failures along the edge of the highway are causing road cracks and pavement settlement.

Other Minor Landsliding

Landsliding coincident with the snowmelt was detected at several other sites this year including minor movement of the Frontier Drive landslide in Morgan County, a small landslide in a highway cut slope in Spanish Fork Canyon, Utah County and a new small slide in a local steep slope in the head of the Sage Vista Lane landslide in Cedar Hills, Utah County.

Shallow landslide in a highway embankment along US-6/89 in Spanish Fork Canyon.	New scarp at top of small local slide in a steep slope in the head of the 2005 Sage Vista Lane landslide in Cedar Hills. Shallow landsliding in 2009 was restricted to the head of the larger landslide.

Rock-wall failure on a residential lot in Bountiful.

Several landslides that occurred in generally south-facing slopes, including an embankment failure along US-6/89 in Spanish Fork Canyon, may have been caused by relatively rapid snowmelt. For the most part, no damage has resulted from these landslides.

Additional Reports:
Update on Springhill Landslide, 2009
Damaging Landslides in Northern Utah, 2006
Sage Vista Lane Landslide, 2005