Major Hwy. 1 mudslide ‘could happen now’ as crews work in Big Sur
When the slippery slope above Big Sur’s Mud Creek slid catastrophically on May 20, 2017 — ultimately burying a quarter mile of Highway 1 with up to 40 feet of mud, rocks and more — U.S. Geological Services scientists already had been tracking the earth’s movement there for decades, according to a recently published study.
What’s more, some of the USGS technologies that detected the earth movement as far back as 1967 also helped keep workers safe during the $54 million repairs to get the roadway re-opened — and the tech is continuing to track potential landslide problems.
Because Mud Creek, Paul’s Slide and other landslide-prone areas of Highway 1 between Cambria and Carmel aren’t out of the woods yet, said John Madonna of John Madonna Construction, which did most of the repairs.
Even if it doesn’t rain any more this season.
Landslides frequently happen when it’s not raining, he said. A major slide “could happen now or in May,” as was the case in 2017. Madonna explained that the danger time is when wet soil starts to dry out, losing the surface tension that keeps things in place.
“It’s like when you take some dry dirt in your hand. Pick it up, squeeze it and let it go. If the soil is totally dry, it will go through your fingers and fall out of your hand. If there’s some moisture in there, it will stay in your hand,” he said.
As his dad, Alex Madonna, told him, “Without any moisture, there’s nothing to hold it together. Even sand will make a ball if there’s some moisture in it.”
John Madonna Construction, Caltrans and others are continuing to collaborate and work on Highway 1, especially in the Paul’s Slide section.
“That was the big slide before Mud Creek,” Madonna said, but even after the repairs were done, the “angle at Paul’s Slide was unsustainable.”
Now, he believes “we’ve found the sweet spot” to increase stability of the steep banks above the roadway.
“I’m really excited about the success that I believe Paul’s Slide is going to be,” he said, “and we should be done with that work by the end of summer.”
There’s still work being done at Mud Creek, too. Monster boulders are being hauled up Highway 1 to bolster the base of the retaining wall there, Madonna said. He said they’re reevaluating to see what else can be done in the next few months to increase stability and safety.
“A tremendous amount of energy came down in Mud Creek,” he said. “We think there’s more up there. There are a few pockets that we’re kind of wondering what they’re going to do.”
With the work completed last summer, he said, “we did the foundation,” but the rest is up to Moth