Historical Landslides in Western North Carolina
Selected landslide events from across the region
Introduction
A landslide is the movement of a mass of rock, debris, or earth down a slope. Landslides are one type of what geologists call "mass wasting"—any movement of soil and rock down a slope that moves as a mostly unified mass under the influence of gravity.
From 1990 to 2016, the North Carolina Geological Survey (NCGS) responded to more than 175 requests for assistance on landslide events from government agencies, the public, and consultants.
NCGS geologists have since investigated over 200 landslides in the Blue Ridge Mountains of western North Carolina. At the time of publication, these landslides have resulted in five deaths, destroyed more than 25 homes and damaged at least 40 others, and impaired nearly 80 roads.
Scroll down to explore historic landslides and debris flows that have occurred across western North Carolina.
To learn more about landslides in general, including where and why they occur, please visit An Introduction to Landslides in Western North Carolina .
Buncombe County
Bent Creek | Debris Flows | 1977
Between November 2–7, 1977, an extratropical cyclone originating in the Gulf of Mexico passed over western North Carolina, causing extensive flooding and triggering debris flows in the Bent Creek area of Buncombe and Henderson Counties and in the Mount Mitchell area of the Black Mountains.
Henderson County
The Great Flood of 1916
Within a week-long period in July of 1916, two back-to-back remnant hurricanes dropped more than 26 inches of rain over western North Carolina, leaving most of the region inundated and its riverways overflowing.
Landslides in western North Carolina triggered by the 1916 hurricanes
The extensive rainfall carried by both storms triggered a number of debris flows, shown in red in the map at left, across western North Carolina. Storm total rainfall contours are shown in blue. Note that the highest rainfall amounts coincide with areas of reported landslides along the Blue Ridge Escarpment—the mountain front that separates the Blue Ridge in the west from the Piedmont in the east. As moisture-laden air from the storm rises against the steep mountain front, it cools and more rain falls as moisture condenses.
Landslides in western North Carolina triggered by the 1916 hurricanes
This shaded relief map color-coded by elevation shows areas (red) where landslides were reported from the July 15–16, 1916, storm.
The Great Flood of 1916
The flooding that resulted from the two storms was dubbed “The Great Flood of 1916.” It's estimated that several dozen people lost their lives during this event—24 of these fatalities were caused by landslides in North Carolina.
Henderson County
Click on the images below for a larger view.
The storms inflicted heavy damage and triggered multiple landslides in Henderson County, shown on the map at right.
Bat Cave
The French Broad Hustler reported that eight lives were lost as a result of flooding and landslides in Bat Cave and Chimney Rock.
Huntley Cabin
One landslide resulted in three fatalities (ages 29, 11, and 8) at the Huntley cabin on Middle Fork Road in Hendersonville.
The Freeman Landslide
Two fatalities occurred in the Freeman landslide along Cox Creek after the 1916 hurricanes. The yellow line indicates the debris flow pathway. The upper image (stability index map) shows where the landslide originated (green dot) within an unstable zone; the lower image shows how the landslide followed the path of a previous landslide.
Hurricane Frances | 2004
Hurricane Frances was the third major hurricane of the 2004 Atlantic hurricane season. Downgraded to a tropical depression by the time it reached western North Carolina, this slow-moving and relatively large storm dropped as much as 23 inches of rain over parts of the region in September of that year.
By September 8, 2004, over five inches of rain had fallen within 24 hours, triggering 92 landslides in Henderson County.
Bear Rock Mountain Estates
The Bear Rock Mountain Estates debris flow in south-central Henderson County was triggered by rainfall from Hurricane Frances in September 2004.
The interactive aerial view at right shows two debris flows in Bear Rock Mountain Estates—click on the scene to rotate, pan, and zoom. The RED DOTS indicate where the debris flows started (landslide points); the AREAS SHADED IN ORANGE show the path of past debris flows (landslide deposits); the YELLOW LINES show the outlines of this event's slope movements (landslide outlines).
The larger flow occurred during Hurricane Frances, on September 8, 2004; the smaller reportedly occurred in the mid-1990s. These debris flows initiated on slopes that were modified by human activity.
Note how the downslope path of the 2004 flow directed the debris into areas known for having historical landslide deposits (the areas in brown.)
This cross-section of the 2004 debris flow in Bear Rock Mountain Estates shows how the slope failure began on a modified slope where a roadway had been constructed. Uncompacted earth was used to create the fill slope underneath the roadway. The road had several generations of pavement cracks, and had failed and been repaired in 1994. Click on the images below for a larger view.
Following the slope failure, the roadway was stabilized mechanically with an earth retaining wall to prevent further debris flows.
Holiday Drive | 2010
On December 1, 2010, over seven inches of rain fell within 24 hours, triggering a debris flow near Holiday Drive in Hendersonville.
This debris flow destroyed a structure as it moved downhill. The images below show different perspectives of the debris flow and the destroyed structure. Click on the images below for a larger view.
The diagram shows how the debris flow moved downhill and impacted the structure.
Macon County
Peeks Creek | 2004
In September 2004, the town of Franklin experienced one of the most intense landslide events in the recent history of western North Carolina.
The debris flow event was initiated as a result of rainfall from Hurricane Ivan, which tracked northeast from northern Georgia to the Tennessee-North Carolina border—a path similar to that of Hurricane Frances, which had passed through the region just 10 days before.
The remnants of Ivan caused extreme rainfall in western North Carolina, and Macon County in particular received some of the highest rainfall amounts from the two hurricane events.
The image shows Ivan's storm track through the Caribbean and over the United States.
Around 10:00 PM on September 16, soil began to liquefy from the excessive rainfall and started to flow down Fishhawk Mountain, approximately 6.5 miles from Franklin. The debris flow continued down the steep terrain to Peeks Creek.
By the time it traveled 2.25 miles to the Cullasaja River, the debris flow had reached a velocity of nearly 33 miles per hour.
In the photo at right, the blue arrow points to Fishhawk Mountain and the debris flow's initiation zone. The yellow arrow indicates the flow's extent.
The debris flow resulted in five deaths and two injuries, with at least 15 homes destroyed. The surrounding area also experienced intense flooding, power outages, and downed trees.
Much of the water had disappeared by the time the landslide reached the homes at Peeks Creek; the debris flow nonetheless inflicted extensive damage to the community.
This former two-story home was pushed 30 feet off its foundation by the debris flow.
Polk County
Pacolet River Valley | Debris Flows | 2018
The western side of Polk County has recently experienced numerous landslides that have caused fatalities and heavy property damage.
Click on the images for a larger view.
On May 18, 2018, a large thunderstorm dumped over 10 inches of rain on the Pacolet River Valley in Polk County, shown in the map above, over a two-day period. The storm caused over 60 landslides, including nine major debris flows.
There were three fatalities associated with the storm—one due to a debris flow and two due to falling trees. A woman was killed by the mudslide as she was leaving her home with her husband along U.S. Highway 176. The woman was outside when the debris flow struck, at around 9:00 PM.
Three other homes were destroyed, many were damaged, and Interstate Highway 26 was closed due to flooding.
The interactive map at right shows the more than 60 debris flows that occurred—click on the scene to rotate, pan, and zoom. The RED DOTS indicate where the debris flows started (landslide points); the AREAS SHADED IN ORANGE show the path of past debris flows (landslide deposits); the YELLOW LINES show the outlines of this event's slope movements (landslide outlines).
Howard Gap Road | Debris Flow | 2018
On December 28, 2018, rainfall from a storm triggered a debris slide on Howard Gap Road. Over four inches of rain fell in 24 hours.
Click on the images for a larger view.
The Howard Gap Road slide still poses a threat to regional infrastructure. The proximity of the slide to Interstate Highway 26, several Duke Energy 44 kV power lines, and emergency public water lines remains a public safety issue.
The interactive map at right shows the Howard Gap Road debris flow—click on the scene to rotate, pan, and zoom. The RED DOTS indicate where debris flows started (landslide points); the AREAS SHADED IN ORANGE show the path of past debris flows (landslide deposits); the YELLOW LINES show the outlines of this event's slope movements (landslide outlines).
Watauga County
Tropical Cyclone | 1940
Between August 13–14, 1940, the remnants of a hurricane that passed through western North Carolina triggered over 2,000 landslides in Watauga County. Together, this group of landslides makes up 93 percent of the slope failures that have been mapped in the county to date.
The 1940 storm began as a tropical depression in the Atlantic Ocean and developed into a Category 1 hurricane before making landfall off the coast of Georgia. As the map to the right shows, the storm moved north and wound through the southeast dropping up to 15 inches of rain throughout the mountains of western North Carolina.
Concentrated areas of high precipitation indicate that the mountains themselves enhanced the storm's effects, lifting its moist air and resulting in increased rainfall.
As the storm passed through western North Carolina on August 13–14, it dropped 13–14 inches of rain over the Watauga County area.
The image at right, shot looking southeast on King Street, shows the flood waters in Boone.
Landslides began in Watauga County on the night of August 13. Over the coming days, the landslides caused 14 deaths and 17 hospitalizations for sustained injuries. They also damaged or destroyed 32 structures in Watauga County alone, and destroyed transportation networks in Watauga and surrounding counties.
In the image to the right, a road crew of about 20 men clear a landslide from an unidentified road in Watauga County, about half of which also collapsed down the embankment in the foreground.
In the image at right, a mill and its flume have been shifted off of their foundation and moved with the debris field by a landslide in the August 13, 1940, flood, probably in the Stony Fork vicinity.
Click on the images below for a larger view.
The mid-August storm and its widespread, intense rainfall most likely triggered many more landslide events in neighboring counties—but this has yet to be confirmed by the NCGS mapping effort.
The landslides triggered by the tropical cyclone were concentrated in two primary areas: Deep Gap/Elk Creek and the Sherwood area, to the northwest of Boone. Deep Gap received over 254 mm (10 inches) of rain within a six hour time period—that’s 1.5 inches per hour, on average. Although a greater number of landslides occurred in Sherwood, those in Deep Gap (which numbered over 700 debris flows) were longer, inundated greater areas, and were more destructive. The largest debris flow mapped in the Deep Gap area was nearly 2,100 meters (~1.3 miles) long. Many of these debris flows deposited sediment in areas of pre-existing debris deposits.
Since 1940, the population of Watauga County has doubled and the number of homes in the county has increased by 80 percent—a number of them near or within the 1940 landslide paths. Altogether, 136 structures (mainly homes) were built between 1940 and 2008 on sites located in the path of 87 of the debris flows from the 1940 event.
If the landslides of 1940 occurred in 2008, they would have severed 329 modern roads.
The image at right shows 1940 slope movement features on 2015 orthophotography. YELLOW DOTS indicate debris flow initiation sites, PINK AREAS indicate 1940 debris flow pathways (landslide outlines), and ORANGE AREAS indicate pre-existing debris deposits (landslide deposits).
Hurricanes Frances and Ivan | 2004
In September of 2004, the remnants of two hurricanes—Frances and Ivan, which arrived nine days apart—struck western North Carolina.
The image at left depicts the track of Hurricane Frances.
The two hurricanes followed similar tracks—this image shows Hurricane Ivan's track. Both travelled along the spine of the Appalachian Mountains, depositing heavy rainfall throughout western North Carolina as they went.
Hurricane Frances moved through western North Carolina between September 7 and 8, dropping 8 to 12 inches of rain on average. It was shortly followed by Hurricane Ivan (image below) between September 16 and 17, which released 6–10 inches of additional rain on average.
Intense rainfall from the remnants of Hurricanes Frances (September 7–8) and Ivan (September 16–17) triggered at least 155 slope movements that caused five deaths, destroyed at least 27 homes, and disrupted transportation corridors throughout western North Carolina.
Nearly 60 of those 155 slope movements occurred in Watauga County.
Fifteen of these debris flows occurred in the same location as 1940 slope movements (the yellow dots on the map at right).
Additional mapping has identified over 150 landslides of differing types that have occurred in Watauga County since 1940.
The map at right shows process points (landslide initiation sites) for Watauga and bordering counties. The yellow dots are initiation sites for the August 13–14, 1940, landslides (mainly debris flows). The red dots are landslide initiation sites that have occurred since 1940.
Landslide damage from Hurricanes Frances and Ivan was countywide and particularly evident in the White Laurel subdivision, three miles east of Boone. Landslides triggered by the intense rainfall caused six houses to be condemned and deemed uninhabitable, including one home that was completely destroyed while its occupants were still inside.
The image at right shows a home in the White Laurel subdivision that was destroyed when an embankment (fill) failure mobilized into a debris flow on September 8, 2004.
This photo was taken from the top of the slope, where the landslide initiated. This is the back of the home.
This image of the same house shows the same slope from the bottom, looking up toward the top.
Notice how the upper part of the home was pushed completely off of the concrete foundation by the force of the landslide.
Landslide Map Viewer
To explore the regional landslide data, visit the interactive WNC Landslide Hazard Data Viewer , which displays data for all counties in western North Carolina that have been mapped to date.
Acknowledgments
North Carolina Geological Survey
- Rick Wooten
- Corey Scheip
- Jesse Hill
- Tommy Douglas
- David Korte
UNC Asheville's NEMAC
- Karin Rogers
- Greg Dobson
- Jim Fox
- Nina Hall
- Ian Johnson
- Dave Michelson
- Kim Rhodes
- Mary Spivey
- Matthew Geiger
- Katie Caruso and Kelsey Hall (interns)