A frigid arctic blast has arrived after a January storm brought over a foot of snow and sleet to the Northeast, which began to melt on Sunday. Tragically, a 12-year-old girl in a Chicago suburb died when a snow fort she built collapsed on her after church. Her 9-year-old friend, who was with her, suffered from hypothermia but is expected to survive. Temperatures dropped to single digits Fahrenheit from New York City to Boston and northern New England, causing melting snow to freeze on Sunday and Monday. The National Weather Service's Marc Chenard in College Park, Maryland, reported wind speeds of 30 to 40 mph, creating dangerously cold wind chills. Chenard stated that the weather conditions are extremely dangerous and life-threatening, with temperatures dropping to the negative 20s in Minnesota and Wisconsin. Boston will be at just 3 degrees Fahrenheit with wind chills of minus 12 or more, while New York City and DC will also experience record or near-record cold, possibly reaching the teens later in the day. The National Weather Service (NWS) has issued wind-chill advisories and warnings for over 10 states, spanning from North Dakota to the East Coast. High temperatures for Monday are predicted to be 17 Fahrenheit in New York City and 12 F in Boston. A large number of Americans were not working on Monday, either because it was a holiday or because they were federal government workers who have been furloughed due to the ongoing shutdown caused by a disagreement over funding for President Trump's border wall. Over 7,500 flights were delayed, particularly in New York and New England, with the number decreasing from over 14,000 on Sunday. The weather on Tuesday will be slightly warmer, with temperatures expected to reach the low 20s Fahrenheit in the Northeast.