NACHES, Wash. — The earth continued shifting Monday at the site of a weekend landslide that obliterated a section of highway, rerouted a river and prompted evacuations in central Washington state.

“It’s still moving, and it may be moving for the next couple more days,” state Transportation Department spokeswoman Meagan McFadden said.

The landslide early Sunday shoved a quarter-mile of State Route 410 into the Naches River, forcing the river to find a new course and causing some flooding. Nearly 80 people were evacuated. Five houses were damaged by the slide, and about 25 more were damaged by flooding. Parts of the roadway were buried under up to 30 feet of rock and debris.

The Transportation Department said Monday it had set up local access for residents to return to grab belongings and secure their homes, but officials asked them to continue staying elsewhere for now.

It was unclear what caused the landslide, McFadden said, but she was quick to knock down a rumor that it was the result of digging at a nearby rock quarry.

“That’s not the case as far as we can see,” she said.

The ground that moved was extremely dry and gave way along a curved section of unstable slope — what’s known as a rotational landslide.

Once the earth stabilizes, workers will be able to get a better sense of how much damage was done, estimate how much it will cost to repair, and figure out where to put a new stretch of SR 410, she said.

The department said its near-term goal will be to restore a road route along the Naches — possibly following Nile Loop Road — within the next three to five days, Jim Hall, director of the Yakima Valley Office of Emergency Management, told The Herald-Republic newspaper.

That can’t be done until the new river channel is rerouted away from Nile Loop Road, which is currently under as much as 3 feet of water.

It may take several more weeks to months to restore the highway.

A 47-mile section of Highway 410 remains closed between Mount Rainier National Park’s Lake Tipsoo and the junction with U.S. 12, five miles west of Naches. A 90-mile detour follows SR 123 over Cayuse Pass.

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Slide blocks SR410 near Naches, forces evacuations