NEW YORK : Thousands of people from the U.S. Midwest to the Northeast were without power Tuesday as biting winds sent wind chills well below zero in some places - snarling air travel, traffic and transit and forcing delayed openings at schools across the region.Many locations in the eastern United States were under wind chill alerts as of early Tuesday with wind chill values dipping as low as 30- to 50 below zero. Wind chills below minus 50 degrees can freeze exposed flesh in 5 minutes.In its advisories, the National Weather Service called the cold “historic and life-threatening,” as the low daytime highs set records. Thousands were without power in the areas hit hardest by the storm, including more than 12,000 customers in the Indianapolis area. Indiana Governor Mike Pence declared a state of emergency for more than 27 counties Monday afternoon.In Illinois, state officials extended the hours of operation for more than 100 warming centers open to anyone needing refuge from the frigid weather and Governor Pat Quinn declared a statewide emergency. The ‘polar vortex’ that froze the U.S. Midwest caused a Northeast weather whiplash Tuesday as temperatures fell 50 degrees overnight as the brutal cold arrived. Buffalo, in New York State, braced for a possible 3 feet of snow and wind chills of at least 30 degrees below zero.New York counties west of the Catskill Mountains expected wind chills of at least 40 below, the National Weather Service said. In Mendota, Illinois, near Chicago, Amtrak passengers from three trains were being transferred to buses to be taken to Chicago after the trains were stuck for several hours because of blowing snow, ABC TV reported. The frigid weather forced Amtrak to scale back or cancel service in states affected by the icy conditions Monday and Tuesday.A blizzard in western New York was expected to create “near impossible driving conditions, with blinding snow conditions during the day Tuesday,” weather service meteorologist Dave Zaff told the Buffalo News.