The freezing cold air from the arctic has arrived after a winter storm in January dumped over a foot of snow and sleet in the Northeast. The snow started to melt on Sunday. In a Chicago suburb, a 12-year-old girl died when a snow fort she built collapsed on her after church on Sunday. The Arlington Heights Police Department reported that a 9-year-old girl who was playing with her was treated for hypothermia after being rescued from the snow and is expected to recover. Temperatures dropped to single digits Fahrenheit from New York City to Boston and across northern New England, causing the melting snow to freeze late on Sunday and early Monday. Marc Chenard from the National Weather Service stated that winds of 30 to 40 miles per hour could create dangerously low wind chills. Chenard emphasized the extreme danger of the current weather conditions, predicting temperatures in the negative 20s for Minnesota and Wisconsin. Boston will be just 3 degrees Fahrenheit with wind chills of minus 12 or lower, while New York City and DC will also experience near-record cold temperatures in the teens later in the day. The 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 expected to reach 17 Fahrenheit for New York City and 12 F for Boston. A large number of Americans had a day off on Monday due to either the holiday or being furloughed federal government workers impacted by the ongoing shutdown, which is the longest in US history. The shutdown is a result of a disagreement over funding for President Trump's border wall plans. Flight delays were reduced to over 7,500 on Monday, down from over 14,000 on Sunday, with most delays occurring in New York and New England. The weather on Tuesday is expected to be slightly warmer, with temperatures in the low 20s Fahrenheit in the Northeast according to Chenard.