Landslides Frequent landslides and erosion along the coast have caused portions of SR 1 to either be closed for long periods of time, or be re-routed entirely. Some of these include: A segment along the coast between Pacifica and Daly City in what is now Thornton Beach was damaged and rendered unusable after a 5.3 magnitude earthquake on March 22, 1957. SR 1 was then eventually re-routed to turn inland to join Interstate 280. The Piedras Blancas Realignment Project plans to re-route the road up to further inland to avoid the expected coastal erosion from the Piedras Blancas Light Station to the Arroyo de la Cruz Bridge in San Luis Obispo County. Big Rock Mesa landslide in September 1983 in Malibu was one of the worst in state history. A total of 250 homes collapsed, cracked or slid off their foundation with 30 homes being condemned. The state agreed to pay forty million dollars as cutting through the hillside to build Pacific Coast Highway was a contributing cause. The Devil's Slide area has been prone to major landslides. One slide in 1995 caused the road to be closed for five months, while another in 2006 led to a four-month closure. The Tom Lantos Tunnels, named after former U.S. Congressman Tom Lantos, opened in 2013 to bypass the area. In 2011, major reconstruction was completed between Muir Beach and Stinson Beach, including the addition of a , , but mostly buried, retaining wall. This followed a four-month, $25 million reconstruction that repaired damage from a 2007 landslide. A March 2011 landslide in the Big Sur region forced Caltrans to close the highway for several months. A section south of Lucia that is also prone to frequent landslides, known as Pitkins Curve and Rain Rocks, was replaced with a bridge and a covered rock shed. During the winter of 2016–2017, the Big Sur region received more than of rain. The road was closed or partially closed due to mudslides and landslides in at least six locations. On February 20, Caltrans declared that the Pfeiffer Canyon Bridge just south of Pfeiffer Big Sur State Park was damaged beyond repair, closing that segment of SR 1 for eight months, and effectively splitting Big Sur in half. Some businesses, cut off from customers and without access to supplies, were forced to close. For some residents, the only means of getting out was via helicopter. In