An arctic blast that is expected to bring snow, ice, and bone-chilling temperatures to tens of millions of people across the United States this week has already proven fatal. The weather was blamed in at least four deaths Monday in the Midwest. The deaths, which authorities in Michigan and Kansas attributed to poor road conditions, occurred as a surge of Arctic air moved east from the Midwest to the Gulf and East coasts. In Chicago, snow and ice ground air traffic to a halt, where more than 2,000 incoming and outgoing flights at O’Hare International Airport had been delayed or canceled as of Monday night, according to the tracking site Flight Aware. On Monday morning, a plane trying to land at O’Hare International Airport slid off the runway. None of the 38 passengers and three crew members aboard an Envoy Air flight from Greensboro, North Carolina, were hurt.