Arctic air descended into the Northeast on Saturday morning, bringing dangerously cold sub-zero temperatures and wind chills that dropped to minus 45 to minus 50 degrees Fahrenheit (minus 43 to minus 45 C) in many areas.
Atop Mount Washington in New Hampshire's White Mountains, the overnight windchill was measured at minus 108 degrees F (minus 78 C), according to the weather observatory at the peak of the Northeast's highest mountain, famous for its extreme weather conditions.
