Hurricane Hector became a Category 4 storm for a few hours early Sunday but then dipped back to Category 3, still a dangerous force, as it headed across the Pacific, threatening to hit Hawaii's Big Island and possibly its active volcano, officials said early Sunday. Hector's winds dropped to 125 mph from 130 mph, the diving line between Categories 3 and 4, early Sunday as it moved westward at 12 mph Sunday, the National Hurricane Center said in an advisory.