Many locations in the eastern United States were under wind chill alerts as of early Tuesday with wind chill values dipping as low as 30- to 50 below zero, AccuWeather.com reported. Wind chills below minus 50 degrees can freeze exposed flesh in 5 minutes.
In its advisories, the National Weather Service called the cold "historic and life-threatening," as the low daytime highs set records.
AccuWeather.com said thousands were without power in the areas hit hardest by the storm, including more than 12,000 customers in the Indianapolis area.
Indiana Gov. Mike Pence declared a state of emergency for more than 27 counties Monday afternoon.
In Illinois, state officials extended the hours of operation for more than 100 warming centers open to anyone needing refuge from the frigid weather and Gov. Pat Quinn declared a statewide emergency.
The polar vortex that froze the U.S. Midwest caused a Northeast weather whiplash Tuesday as temperatures fell 50 degrees overnight as the brutal cold arrived. Buffalo, N.Y., braced for a possible 3 feet of snow and wind chills of at least 30 degrees below zero.
New York counties west of the Catskill Mountains expected wind chills of at least 40 below, the National Weather Service said.
In Mendota, Ill., near Chicago, Amtrak passengers from three trains were being transferred to buses to be taken to Chicago after the trains were stuck for several hours because of blowing snow, ABC's "Good Morning America" reported.
The frigid weather forced Amtrak to scale back or cancel service in states affected by the icy conditions Monday and Tuesday.
A blizzard in western New York was expected to create "near impossible driving conditions, with blinding snow conditions during the day Tuesday," weather service meteorologist Dave Zaff told the Buffalo News.
Gov. Andrew Cuomo declared a state of emergency in 14 western counties and shut parts of the state's key east-west interstate highway.
The blizzard was one component of a massive cold front flowing from the polar vortex arctic cyclone that plunged most of the country into numbing temperatures Monday and Tuesday.
"The cold temperatures with the gusty winds will result in dangerously cold wind chills across most of the Eastern Seaboard," the weather service said early Tuesday.
High temperatures in much of the Northeast dropped from the mid-50s Monday to single digits overnight. The plunge was compounded by sustained 20- to 30 mph winds, and gusts topping 50 mph, making the temperature feel at least 20 degrees colder.
FlightAware.com reported 1,028 flights were delayed and 2,026 flights across the United States were canceled by midmorning Tuesday.
Temperatures in Chicago and Milwaukee -- both on Lake Michigan -- were expected to rise to 4 degrees above zero Tuesday, AccuWeather said. Wind chills would make it feel like 11- to 13 below.
The high temperature in Minneapolis was forecast to be minus 1, with wind chills approaching minus 35.
Most Midwest colleges and universities said they would resume classes by Tuesday afternoon although Northwestern University, which had no classes Monday, remained closed, the Chicago-area university said.
Hundreds of school districts, from North Dakota, Minnesota and Wisconsin east to Ohio and as far south Tennessee, also remained closed because of the single-digit cold.
Other school districts, including in North Carolina and parts of Louisiana, said they would be on 2-hour delays.
Raleigh, N.C., was reached a low of 9 degrees at 6 a.m. Tuesday, breaking the record low of 15 degrees for the day set in 1988. Baton Rouge, La., dropped to 18 degrees.