LOCHSLOY — There still are pieces of concrete and rebar from where the Pilchuck River swallowed the house in 2012.

Now the river is eroding toward Highway 92 between Granite Falls and Lake Stevens. Behind an orange-and-white barrier, waist-high posts mark the distance from the highway — 40 feet, 50 feet, 60, 65.

There is no marker at 70 feet. That’s where the ground ends and the river begins.

The drop-off, at least 20 feet with the river winding below, is picturesque on a mild, sunny winter afternoon. But when the river is swollen, it gnaws at the eroding cliff, undercutting where the driveway once was for the home that stood here.

A $4 million state project is being designed to save the highway before erosion reaches the two-lane road. In the meantime, crews are monitoring the river’s proximity to the pavement. Officials are confident they have time before the highway becomes unsafe, but exactly how long depends on the Pilchuck. It’s a familiar story for infrastructure around the county: the river is unpredictable.

Two years ago, Clayton and Catherine Bess lost their retirement home at 7207 Highway 92 to the same sharp meander in the Pilchuck. The river flooded in February 2012. Their house went first, then the garage. A short gravel drive and white pipes that jut out of the ground are the only remaining evidence of the home. When the river runs low enough, you can also see a jumble of concrete and rebar in the water below.

Bob Krull, a 78-year-old Boeing retiree, lives about two miles from the former Bess home. He remembers when the river claimed the house, and he’s been concerned about the erosion since.

Last week, Krull and his wife stopped to look at the site. Krull isn’t worried about his house, a couple of miles from the river, but he knows the highway is an important route for commuters and for truck drivers who haul loads from local quarries.

“The river is right there,” Krull said. “It’s really, really close. If they don’t do something, it’s going to undercut the highway, and that would be a disaster.”

The state is reviewing options to protect the highway, said Travis Phelps, a spokesman for the state Department of Transportation. Maintenance crews check the site weekly.

“We still have quite a bit of time before the river becomes an immediate threat to the highway,” Phelps said. “Part of what we need to do is work with the county and others to look at the floodplain there. We want to make sure whatever fix we find there won’t just kick things down the road and create other problems.”

The county is aware of the problem and will get involved if any county roads become threatened, spokeswoman Rebecca Hover said.

Officials hope to finalize in 2016 a design for the state project, which has been awarded funding. Construction could start as soon as 2017, but crews have a limited window to work alongside the river because of fish migration, Phelps said.

In the meantime, the highway is safe for cars and trucks. Traffic could be funneled to one lane or rerouted via detours if needed, but Phelps doesn’t anticipate narrowing or closing the road in the coming year. However, the department will continue to keep an eye on the river where it’s been eating away the earth.

“The typical erosion you see is that undercutting, and then the top kind of falls in,” Phelps said. “We’re definitely monitoring that. We have time.”

Herald writer Noah Haglund contributed to this report.

Kari Bray: 425-339-3439; kbray@heraldnet.com.