WASHINGTON—Floods hit parts of the Northwestern United States on Friday after heavy rains, while a winter storm brought more than a half a foot (15 cm) in snow in the eastern parts of the country, closing schools, offices, and busy roads. Flood and gale warnings are in place across many coastal areas in the Pacific Northwest, whilst winter storm warnings remained for eastern parts of Maine, according to the National Weather Service. “One final storm system will move across the Northwest today with heavy coastal rain and heavy mountain snow,” it said. Several alerts were affecting a number of major roads in Washington state, with “hazardous water conditions” closing a number of sections, the Washington State Department of Transportation said. Some properties, roads, and fields were seen deep in water in images and videos posted on social media and by local news outlets. Around 2,600 flights to, from, and within …