SOUTH LAKE TAHOE, Calif.—A ferocious wildfire swept toward Lake Tahoe on Tuesday just hours after roads were clogged with fleeing cars when the entire California resort city of South Lake Tahoe was ordered to evacuate and communities just across the state line in Nevada were warned to get ready to leave. The popular vacation haven normally filled with tens of thousands of summer tourists emptied out Monday as the massive Caldor Fire rapidly expanded. Vehicles loaded with bikes and camping gear and hauling boats were in gridlock traffic, stalled in hazy, brown air that smelled like a campfire. Police and other emergency vehicles whizzed by. “It’s more out of control than I thought,” evacuee Glen Naasz said of the fire that by late Monday had been pushed by strong winds across California highways 50 and 89, burning mountain cabins as it swept down slopes into the Tahoe Basin. More firefighters …