At 770 feet, Northern California's Oroville Dam is the tallest dam in the United States -- 44 feet taller than the Hoover Dam. Hundreds of thousands of people were evacuated from towns below the lake on Feb. 12, 2017, after the reservoir swelled from recent rains and the emergency spillway flooded, threatening to send a 30-foot wall of water into nearby communities.
The dam, located in California's Sierra Nevada foothills, is about 75 miles north of Sacramento. Oroville Lake stores winter and spring runoff from the Sierras. That water is then released into the Feather River to meet the California's water needs. One of California's most significant state water projects, the Oroville and Feather River project started in 1957, first relocating Highway 70 and the Western Pacific Railroad before dam construction began in 1961. The dam itself took nearly six years to complete. A spillway was finished in February 1968. Then-Gov. Ronald Reagan and family members, including wife Nancy, visited the site for its dedication. An estimated 3,500 people attended the dedication and a parade in downtown Oroville later that day.