(Reuters) - A section of highway winding along California’s breathtaking Big Sur coastline will probably remain closed for months by damage from a massive landslide unleashed by a rain-soaked hillside over the Pacific, state transportation officials said on Wednesday.

A massive landslide is seen in this Caltrans aerial photo of a quarter-mile section of State Route 1 about 100 miles south of San Jose, California, U.S. in this photo released on May 24, 2017. Courtesy of John Madonna Construction/Caltrans/Handout via REUTERS

After the wettest winter on record in the state, the collapse marked the third major closure in Big Sur, a roughly 76-mile stretch of the Pacific Coast Highway that hugs California’s rugged Central Coast between Cambria and Carmel-by-the-Sea.

The Big Sur portion of State Route 1 is designated as a National Scenic Byway for its spectacular coastal vistas and is famed as one of the longest stretches of largely undeveloped shoreline in the continental United States.

Saturday’s slide, one of the region’s largest in decades, deposited a mound of rocks and other debris some 35 feet deep along a quarter-mile section of the highway, about 100 miles south of San Jose, California Department of Transportation (CalTrans) spokesman Colin Jones said.

An estimated 1.5 million tons of material was dumped onto the road and the shoreline below at Mud Creek in an area adjacent to a smaller slide that had already closed that section of the highway.

“I think it’s safe to say it will be several months before it reopens,” Jones said by phone. “We haven’t even been able to get in and assess the damage and come up with a plan.”

Jones added that it may be necessary to reroute the highway entirely around the damaged section.

The affected area is not the busiest portion of the highway. Still, during summer tourist season, as many as 6,000 vehicles a day typically pass through the stretch of road blocked by the landslide.

The Mud Creek blockage is the southernmost of three major road closures in effect along a 36-mile stretch of the Big Sur coast, forcing lengthy detours for motorists.

Severe erosion led highway officials to shut down a bridge in Pfeiffer Canyon in February, and a March landslide closed a stretch of the road near Lime Kiln State Park. The bridge is not expected to reopen until late September, Jones said.

“Typically when it rains for a few days, you can expect small slides that our maintenance crews can clean up in a few hours,” Jim Shivers, a CalTrans spokesman, said by phone on Wednesday. “These are way beyond the scope of what we’re used to responding to.”