A Passaic man is dead after a heavy tree limb came crashing down during a Mother's Day backyard barbecue. It happened at around 4:30 yesterday afternoon when lightning struck a tree on Paulison Avenue during a flash storm. A 28-year-old man, a young father, was killed. Six other people were hurt, suffering mild to moderate injuries. The sudden storm took down trees in several other northern New Jersey communities, including Rutherford and Fair Lawn, hitting parked cars and train tracks, but in those communities, no one was hurt.