A major winter storm is raking the Atlantic Seaboard, bringing high winds, coastal flooding and heavy snow to cities as far south as Savannah, Georgia, and parts of northern Florida. Meteorologists describe the storm as a “hyper-bombogenesis” that rapidly dropped pressure and quickly intensified over the Atlantic. Forecasters predict the storm will be followed by bone-chilling temperatures as a “polar vortex” returns to much of the U.S. later this week. Last month, President Trump cited cold winter weather in the U.S. to repeat his claim that global warming is a hoax, but climate scientists say greenhouse gas emissions may be contributing to such weather events.