Sept. 12 update:
Rock scaling will begin Tuesday, September 20, at the top of White Bird Grade to stabilize the slope above U.S. Highway 95. Work over the next several weeks will intermittently affect the highway.
Scaling involves knocking down loose debris proactively, with rocks falling from the hillside down to the road. Specialized equipment will excavate rock at the top and flatten the slope.
“At least for the first day, we’ll have flaggers there to stop all traffic for 20 minutes at a time while workers are scaling,” Operations Engineer Jared Hopkins said.
Work is scheduled Monday through Saturday, with construction starting each day at daybreak.
“As work continues, we may allow traffic to flow without being stopped during work if it is safe to do so,” Hopkins said.
Metal containers that have been shielding drivers since the rockslide in May at this location will be shifted back on to the highway. The passing lanes will be closed earlier, forcing drivers to merge sooner. When crews are not on site, traffic will flow freely over the hill with one lane in each direction.
Drivers are encouraged to check road conditions at 511.idaho.gov.
May 11 update:
All lanes on U.S. Highway 95 are now open after the Idaho Transportation Department removed debris from a rockfall on Monday morning and placed barriers to protect drivers.
One lane had remained open immediately following the rockfall. New railroad containers have taken the place of concrete rail to offer better protection should more rocks come down.
“More rocks fell down this morning. The slope is not stable,” Operations Engineer Jared Hopkins said. “This will not be a quick fix.”
The department is working to secure an emergency contract to further assess conditions and then likely use specialized equipment to scale the slope. Scaling involves knocking down loose debris proactively.
May 9 update:
Following persistent rain over the last week, a rockfall blocked lanes this morning on U.S. Highway 95 at the top of White Bird Grade south of Grangeville. The highway remains reduced to one lane.
Rocks ranging from 6 inches to 6 feet wide blocked the southbound lane around 10 a.m. Crews immediately responded by alternating northbound and southbound traffic and hauling away debris.
Rocks continued to fall down the slope, prompting the Idaho Transportation Department to place concrete rail to protect drivers. A spotter will watch the hillside through the night, ready to close the highway at a moment’s notice. Flaggers will control traffic through tonight and likely tomorrow night.
“This happened during blue skies,” Operations Engineer Jared Hopkins said. “Just a reminder that sometimes it takes a bit for rain to seep into a slope and make it unstable.”
Experts will continue to monitor the site. The department is arranging for large railroad containers to be placed at the edge of the highway to block any future rockfall.
“We will let this settle overnight, but in the morning our goal is to continue removing debris,” Hopkins said. “Once larger barriers are in place, we’re hopeful to have one lane in each direction while we identify a long-term solution.”
The department is also working to secure an emergency contract to use specialized equipment to scale the slope, a process that involves knocking down loose debris proactively.
Drivers are encouraged to monitor road conditions at 511.idaho.gov.