DeKalb County, Ala., Emergency Management Officer Michael Posey assesses the breakdown of Adamsburg Road going up Lookout Mountain from downtown Fort Payne, Ala., Thursday. The agency closed the Highway 78 road Wednesday after police spotted fissure.

A mudslide that caused a nearly 100-foot section of Fort Payne Gap to sink has forced officials to close the road for at least three months.

Officials said the closure on County Road 78 up Lookout Mountain is expected to cause extra congestion, as the alternate route on state Highway 35 is down to just one lane for repairs to a crack in the road.

"It adds that much more traffic going that way," DeKalb County Engineer Ben Luther said.

The mudslide caused the outside shoulder of the road, which is on the side of the steep mountain, to sink about 8 inches. That situation is unsafe along a sharp curve, Luther said.

Now experts have to decide how to fix the road, he said; whether to carve out the dirt and rebuild the highway or drive giant rods into the earth to brace the road and keep it from falling down the embankment. Contractors are examining the road to decide which is the safer option, he said.

For drivers going to and from Fort Payne, the trip up and down the mountain will involve a five- to six-mile detour on Highway 35 and a 14- to 15-mile drive south down U.S. Highway 11.

Road officials have known there was a crack in the roadbed for more than a year, but the recent rain has made the situation worse, DeKalb County Emergency Management Agency director Anthony Clifton said.

"This is an ongoing problem," he said. "All this rain has caused it to be the final straw that broke the camel's back."

Officials also are examining to see whether additional traffic from drivers avoiding the road work on Highway 35 has caused too much stress on the road, Clifton said.

They predict the repairs will take a minimum of three months, but the work could take longer depending on the weather. Officials have to go slowly and decide how to fix the road for fear crews could make the problem worse, Luther said.

"We really don't know the extent of the [road] failure," he said. "We're concerned [about] going in and digging and making it worse."