Temperatures dropped below minus 40 in two northern Colorado towns Tuesday morning during the worst hours of the four-day arctic blast that hit the state over the weekend. National Weather Service meteorologists said the towns could have been the coldest places in the country this morning,

Hundreds of flights at the Denver International Airport were delayed and canceled, and there were several traffic jams and road closures during whiteout conditions. An extreme cold warning was issued for places that reached or were likely to reach minus 25 to minus 35 degrees.