As workers continued to dig out loose rock beneath Signal Mountain Boulevard on Saturday, another Hamilton County mountainside began giving way and fell to the road along Lookout Mountain's Scenic Highway.
Three times in about the last month, rocks and earth gave way and closed major traffic arteries in the area. The first slide, on Nov. 10 along U.S. Highway 64 in Polk County, will take two months to clear, officials said.
The second, early Wednesday on Signal Mountain Boulevard, caused that road on the side of the mountain to collapse early last week. It may be reopened in two weeks, state transportation personnel said.
On Saturday evening, two truck-size boulders fell to the road on Lookout Mountain and were resting in a ditch, according to Chattanooga police spokeswoman Sgt. Jerri Weary.
Highway workers in Hamilton County, upon seeing the size of the boulders and spotting some "questionable" trees, decided to close Scenic Highway for the night, said Tennessee Department of Transportation region spokeswoman Jennifer Flynn.
Officials won't know the extent of the problem until first light this morning.
"A geologist has been notified but won't re-examine the area until daylight. Until then, the roadway has been closed," Sgt. Weary said in a news release.
TDOT documents show there are three sites in Hamilton County among 36 across the state believed ready to generate a rock slide at any time. Two are on Lookout Mountain some distance from Saturday's slide, and the third is on Signal Mountain near Wednesday's slide.
Repairing those most-dangerous sites "would cost major money to be spent to totally repair these roadways," Ms. Flynn had said previously. "We have so many sites like that across the state; it's just impossible."
A surplus of rain and freezing temperatures has aggravated vulnerable mountainsides, geologists say. Water acts like a lubricant for the slides, and the freezing-thawing action loosens the stone.
On Lookout, highway workers thought if overnight rains fell hard, there was a greater chance more rock would come down.
"If it rains, it's more likely that more will come down onto the road," said Robert Shipley, the highway worker called to the scene.
He said the giant boulders hit a sign and were resting just on the road's edge.
In Polk County, when 3,000 truckloads of rock fell to the road on Nov. 10, highway workers were on the scene busting up big boulders just minutes before the mountainside let loose and wiped out the roadbed.
PROGRESS ON SIGNAL
Highway repair contractors worked through the day and overnight Saturday to repair the gaping hole in Signal Mountain Boulevard, officially U.S. Highway 127.
"They are about two-thirds done with their excavation," Ms. Flynn said, explaining workers were on track to finish on time.
Contractor Wright Brothers Inc. worked Saturday and through the night to repair the earth beneath the road, where a major hole developed after Tuesday night and Wednesday morning rains. Tennessee Department of Transportation officials said one lane of traffic should be open by Monday at 6 a.m.
On Saturday night, dump trucks lined the highway and one at a time dumped rocks onto the cleared-out slope, Ms. Flynn said. The rocks must be placed in the crater before a new road surface can be built, she said.
Signal Mountain police and Hamilton County sheriff's deputies will be on duty from 7 a.m. until 7 p.m. today to help motorists negotiate the curves at the top of the W Road, Town of Signal Mountain Mayor Bill Lusk said in a Saturday news release.
"We anticipate that officers will continue to assist traffic at the W curves during weekday commute hours until repairs to Signal Mountain Boulevard are completed. We thank citizens for their patience" and the deputies for their assistance, Mr. Lusk said in the statement.
Local residents had a difficult time going up or down the mountain Saturday using the W Road.
Motorists had to wait more than an hour on that road after a stalled truck blocked traffic early Saturday afternoon, a Signal Mountain police dispatcher said.
The road was backed up most of the day, said Janice Atkinson, Hamilton County Sheriff's Office spokeswoman.
Signal area traffic problems were the worst in the afternoon, when Roberts Mill Road also was closed because of water and ice, Ms. Atkinson said. That road was reopened by early evening, she said.