The freezing cold air from the Arctic arrived after a winter storm in January brought over a foot of snow and sleet to the Northeast, which began melting on Sunday. In a Chicago suburb, a 12-year-old girl tragically died when a snow fort she had built collapsed on her after going to church on Sunday, as reported by the Arlington Heights Police Department. A 9-year-old girl she was playing with suffered from hypothermia after being rescued from the snow, but is expected to survive, according to the police. Temperatures dropped to single-digits Fahrenheit (-20 C) from New York City to Boston and northern New England, causing the melting snow to freeze late Sunday and early Monday, as stated by Marc Chenard at the National Weather Service’s Weather Prediction Center in College Park, Maryland. The strong winds reaching up to 30 to 40 miles per hour (48-64 kph) brought dangerously cold wind chills. According to Chenard, the weather is extremely dangerous and life-threatening, with temperatures in the negative 20s expected in Minnesota and Wisconsin. Boston will be around 3 degrees Fahrenheit with wind chills of minus 12 or lower, while New York City and DC will be in the teens later on. The National Weather Service has issued wind-chill advisories and warnings for over 10 states, spanning from North Dakota to East Coast cities. High temperatures for Monday are predicted to be 17 Fahrenheit for New York City and 12 Fahrenheit for Boston. A large number of Americans had the day off on Monday due to either the holiday or being furloughed federal government workers amidst the longest shutdown in US history. This shutdown is a result of a disagreement over funding President Donald Trump's plans for additional barriers on the US-Mexico border. Flight delays, particularly in New York and New England, decreased to over 7,500 flights on Monday from over 14,000 on Sunday, according to FlightAware.com. The weather on Tuesday is expected to be slightly warmer, with temperatures in the low 20s Fahrenheit in the Northeast, as stated by Chenard.