A winter of epic snow and rain had brought California’s “phantom lake” back to life — and threatened towns and farms in the process. So bountiful was the harvest that white settlers named the area Mussel Slough, and commercial fishermen in the 1870s plied the lake in schooners and steamers and caught terrapin turtles served as delicacies in San Francisco restaurants. Its traditional songs include passages that say when the water rises, “that’s the lake telling us, ‘OK, it’s time for you guys to get out of here now,’ ” said Robert Jeff, the tribe’s vice chairman