What you should know about landslides
Most people don’t think very much about landslides. There are reasons why you should.
Landslides can happen almost anywhere, not just on mountains or steep slopes. They can happen across a variety of landscapes, including in developed residential areas, on cultivated lands such as farms, and in forests. They 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.
Some other key landslide takeaways:
- Landslides are triggered primarily by natural occurrences (like rain, melting snow, stream erosion, changes in surface- or groundwater levels, earthquakes, and volcanoes) and by human activity.
- Extreme weather patterns (think periods of above-normal rainfall or drought) are associated with a changing climate, and are already impacting people. These extreme weather patterns are also linked to landslide events.
- Landslides usually occur in areas where they’ve happened before. Mapping where landslides have happened in the past can help us identify where they might happen again.
And—as you can see from the picture at the top of this story—landslides are also a hazard of particular concern to those of us who live and work in western North Carolina.
Given all of the above, it makes sense that landslide mapping and resilience planning can support efforts by emergency responders, planners, and city and county staff to be better prepared to help protect people and assets from losses associated with landslides.
To that end, we’ve been working with a team of fine, fine geologists at the North Carolina Geological Survey (NCGS) to bring their landslide mapping and hazard data to decision makers and the public. Today, we’re launching a new suite of tools that allows users in North Carolina to consider their landslide hazard risk.
The new website—Landslides in Western North Carolina—includes an interactive mapping tool, a guided data tutorial, educational materials, and more.
The website hosts digital narratives with easy-to-understand information, providing an introduction to landslides and the story of how historical landslide events have impacted the region. Downloadable educational materials and links to further resources are also included.
The site’s featured tool is the WNC Landslide Hazard Data Viewer. This digital viewer displays map-based information on over 4,500 landslides mapped by NCGS, including landslide initiation points and historic and potential flow pathways. For some counties, the viewer also displays a Landslide Hazard Ranking, which designates areas ranked at moderate or high risk of landslide occurrence in response to an extreme precipitation event (more than approximately five inches of rain over a 24-hour period).
The project is the product of the Hurricane Recovery Act of 2005, which directed the North Carolina Department of Environmental Quality (NCDEQ) to provide maps of landslide vulnerability for the 19 western North Carolina counties suffering the greatest damage from Hurricanes Frances and Ivan. The NCGS, a unit of NCDEQ, partnered with NEMAC to support the data delivery and visualization of accurate, current, and useful landslide data through this suite of web products,
Check it out and let us know what you think!
