Friday, January 9, 2009

Slip Sliding Away

After all the recent rain, I’ve seen brooks and rivulets where I haven’t seen them in a long time. But what’s good for groundwater supplies and stream levels isn’t always so good for houses built on precarious slopes. Two people miraculously escaped death when their new house in Maggie Valley tumbled down the mountain this week.

The devastation was similar to that of a deadly landslide that destroyed a Maggie Valley home in 2003, shown here in a North Carolina Geological Survey (NCGS) photo:

The Asheville Citizen-Times has posted a photo gallery of the latest disaster:

[click on map to enlarge]

The NCGS has prepared a map of Jackson County identifying sites where landslides and debris flows have already occurred, and is preparing a highly detailed map of landslide hazard areas. So far, the agency has completed maps of Macon and Watauga counties. The Macon maps were the first in the series, and identify slope movements and downslope hazards.

You have to wonder how these maps are going over with the developers of gated golf-course enclaves (I need to quit calling them "communities") where some of the more precarious houses have already been built. I doubt that a complimentary copy of the landslide hazard map will be sent out with the glossy real estate porn peddled by Legasus and its competitors.

But it should be.

Many of these big developers in WNC are subject to the Interstate Land Sales Full Disclosure Act, a federal law intended to protect consumers from fraudulent and abusive land sale practices. Landslides and erodible soils are common in the region and these hazards must be revealed. Failure to disclose material facts is a violation of the Act. More information on this issue is available at:

Over the course of a few days in 2004, the aftermath of Hurricanes Frances and Ivan resulted in 130 landslides, 5 deaths (Peek’s Creek) and 27 houses destroyed. That kind of information is not in the sales brochure.

But it should be.

For details on the landslide hazards in WNC, I can recommend two websites:

Introduction to Landslides, North Carolina Geological Survey

and The NC Mountain Landslides Website

One thing I’ve learned from these sources – signs of old landslides and debris flows are quite evident to the trained eye. And another helpful bit of information – curved trees can indicate a slow-moving landslide. From NCGS:

A clue that the land is moving is trees growing at an angle or with bent trunks as shown below. Trees growing on the side of a hill normally grow straight up. If the land is slowly moving downslope, the trees will lean, but keep trying to grow straight towards the sun. This process results in their bent growth pattern and indicates the trees are slowly sliding down the hill on top of the landslide. This should be a warning that the land may move substantially with the next large rainstorm.

I’ll bet that bit of mountain lore isn’t in the sales pitch.

But it should be.

Finally, among the many landslides to date in WNC, I don’t know that any have been captured on video, but a recent landslide in Japan was recorded and demonstrates how quickly and dramatically a mountain slope can collapse. Powerful stuff.

1 comment:

Western North Carolina Writer's Underground said...

Good video of that Chinese land slide. Until you actually see a slide its hard to imagine the terribleness and beauty (power and majesty?) of this manifestation of nature. Harvey Broome in his journals (published as "Out Under the Sky of the Great Smokies") remarks about slides on Mt. Leconte and their power.

The "should be's" in your post could become reality in a strengthened subdivision and steep slope ordinances. All we have to do is to re-write them and push for the changes. It can be done.