What makes I-77 so scary

I wrote in this blog about two years ago on the dangers of driving on Interstate 77 at Fancy Gap Mountain, on the North Carolina-Virginia border.

That danger was brought to life Sunday afternoon, in a huge crash that enveloped nearly 100 vehicles, killed three people, injured 25, and forced the road to be closed for many hours.

It wasn't a first.  That section of road has been the scene of several huge wrecks, and it's really difficult to see how things will change in the future.

Along that stretch of road, I-77's elevation changes from about 1,500 feet in North Carolina to about 2,800 feet at the top, in Virginia. Much of that altitude change happens in a 6.2-mile stretch. It's less scary northbound, because everyone is climbing, and that limits the speed at which most vehicles can drive.

But southbound, from Virginia into North Carolina, is an adventure. As I wrote in 2011, tractor-trailers, other types of trucks, campers, SUVs, minivans and regular sedans tend to fly down that mountain, and they often roll into a thick fog bank that forms on the embankment.

It's actually the Blue Ridge Escarpment, and it's where the North Carolina Piedmont rises into the Appalachian Mountains. That change in topography occurs all along the mountain line in North Carolina, but it's particularly vivid on I-77 because of the high traffic volume and the unusual makeup of the ridge in that area.

Dave Wert, of the National Weather Service office in Blacksburg, Va., said the Blue Ridge line typically is southwest-northeast, but it's on more of an east-west line in the Fancy Gap, Va., area at I-77.

When a moist south or southeast wind from the Atlantic or Gulf of Mexico piles up against the mountain range, it forms dense fog. And when the wind is strong out of the south -- as was the case late Sunday -- it creates a tunnel effect up I-77. Winds can blow at 40 to 50 mph, causing motorists to lose control of their vehicles.

The fog-induced wrecks can be nightmarish. One minute, you're driving south on I-77 in cloudy weather. The next minute, fog limits visibility to a 100 or 200 feet.

The Virginia Department of Transportation did a study on that section of I-77 about a decade ago and found that most of the wrecks happened between mile markers 5 and 7 (Sunday's started near mile marker 6), about halfway down the steep grade. And most happened on the southbound side, where motorists were traveling faster.

So Virginia officials installed devices to measure fog and wind, and to alert motorists in advance with overhead signs. Unfortunately, the warnings sometimes don't slow motorists.

Before this section of road was completed in July 1977, motorists headed from North Carolina to Virginia had to use twisting, turning U.S. 52. A trip of 10 miles could take a couple hours, and portions of that roadway were scary, too.

Nothing can be done about the fog that forms on the mountain and the strong winds that sometimes blow there.  Apparently, nothing can be done about the motorists who charge down the mountain at 75 and 80 mph, seemingly ignoring the electronic signs that warn of dense fog ahead.

It leaves the rest of us at great risk.