PORTLAND (AP) — A main highway to the Oregon coast blocked by a mudslide remained closed Wednesday as crews cleared the road but couldn’t keep water off it.

Once a concrete culvert 7 feet in diameter is unplugged and two smaller culverts are installed, U.S. 30 might reopen Thursday morning to one lane of traffic, with flaggers letting vehicles through in one direction, then the other, said Christine Miles.

“If everything goes well, it could be sooner than that,” she said Wednesday afternoon.

Miles said crews would work through a second night after using heavy equipment to shove a soupy mixture of gravel, mud and trees off the highway.

But the water still running over the highway remained a hazard to vehicles and a threat to wash out the roadbed.

Nobody was injured in the slide Tuesday that covered an estimated three football fields in length. But two homes were destroyed and others were hit by the slide.

U.S. 30 runs along the Columbia River, linking Portland to Astoria on the coast. The area hit by the slide was part of the region damaged by recent major storms.

Mudslides are not uncommon in a region with steep slopes, weak rock beneath the soil and heavy winter rains, said Jason Hinkle, a geotechnical specialist with the Oregon Department of Forestry.

More than 10 inches of rain fell on some parts of the Oregon Coast Range during the two storms.

“When you get that much water in that soil, it’s basically a lubricant,” said Rod Nichols, a spokesman for the forestry department.