HARPERS FERRY – Next summer crews could begin installing rockslide safety barriers along the Loudoun Heights cliffs beside U.S. 340, a state highway official reported.
Final design details of the safety measures are being worked out with U.S. National Park officials, according to Lee Thorne, a state highway engineer.
A public meeting on the designs is tentatively planned for later this month, Thorne said. Notices will be sent whenever a date and location are arranged, he said.
After examining the craggy cliffs above U.S. 340 in January 2018, a Pennsylvania geological engineering firm recommended about $14 million in safety measures for the highway between Chestnut Hill Road and Harpers Ferry Road. Those measures include rock bolting, berms and barriers.
“There will be a variety of methods used, depending on the particular type of hazard,” Thorne stated in an email.
Different barriers or metal mesh were suggested in various combinations for certain geological conditions—from overhanging ledges to saplings growing out of crevices—found along the three slopes studied.
State highway officials are aware of several instances when rocks and boulders have tumbled onto the highway, according to a 2018 report by HDR Engineering of Pittsburgh. “A majority of failures that occur along U.S. 340 are rockfalls of minor volume and impact,” the report states. “However, large rockfall events have occurred in the past and will pose a risk in the future.”
Last February, a woman from Knoxville, Maryland, was injured after driving her car head-on into a boulder blocking the eastbound lane of U.S. 340 below Loudoun Heights.
The woman’s car struck a boulder about 10 feet in diameter about 15 minutes later, police said. She was treated for injuries that were not life-threatening. However, her car was heavily damaged in the early morning accident.
State highway crews removed the boulder and other smaller rocks from the roadway about one-quarter mile west of the Virginia line near Harpers Ferry Road.
No other collisions or injuries were reported.
Sgt. Robert Sell, a senior accident investigator for the Jefferson County Sheriff’s Office, said people report rock hazards about a dozen times a year on U.S. 340 between Chestnut Hill and Harpers Ferry roads. More reports occur during freeze-and-thaw weather cycles in winter and spring, he said.
Most rockfalls along the highway appear to occur during rapid freezing and thawing cycles in winter and spring, the report states. Groundwater regularly seeps from different spots along the cliffs, according to the HDR Engineering report.
U.S. 340 is considered a major traffic corridor for motorists traveling into and from West Virginia. Traffic counts conducted three years ago found more than 31,000 vehicle trips are made daily on that 45 mph section of the highway. That’s about half of the volume of traffic that was flowing on Interstate 81 at Martinsburg at the same time, state highway officials said.