At least 17 people were killed, more than 700,000 homes had no power and thousands of airline passengers were stranded across the country Saturday as a powerful winter storm created the nightmare before Christmas.Record-breaking cold gripped the US along with white-out conditions in some areas and ferocious winds in others — while a “bomb cyclone” hit portions of the nation.A “bomb cyclone” is created when the atmospheric pressure drops quickly in a strong storm.Pittsburgh, Charleston, S.C., and Washington, DC, were all expected to hit record lows for Christmas Eve.Fargo, ND., was forecast to be the coldest spot in the country on Christmas.The death toll from the massive storm — which stretched from the Great Lakes to the Mexican border — included one man in the Big Apple, and three in upstate Erie County, where hard-hit Buffalo was expected to get up to 4 feet of snow by Monday.“It is life-threatening what is going on as we speak in Buffalo,” Gov. Kathy Hochul said Saturday, noting al...