Thousands of doctors and nurses will bunk at hospitals, an emergency operation center will be set up and Southern California residents are being urged to stay home and stock up on food. One major airline offered $4 seats to help people avoid the looming mess, selling out of tickets in three hours. The crisis? A 10-mile stretch of Interstate 405 — a vital artery that links population centers north and south of the Santa Monica Mountains — is shutting down for 53 hours this weekend. The closure, a necessary part of a major highway reconstruction project, is being dubbed "Carmageddon,"...