Sinkholes swallowed cars and floodwaters swamped towns and swept away a small boy as the US state of California was wracked by more wild winter on Tuesday, while the next in a powerful string of storms loomed on the horizon. Millions of residents faced flood warnings, nearly 50,000 people were under evacuation orders, and more than 110,000 homes and businesses were without power because of heavy rains, lightning, hail and landslides.