New York Chill map
© MyFox NYCold Weather: Wind Chills that were recorded across the region on Tuesday morning at 8 a.m.
The coldest, most dangerous blast of polar air in decades gripped the country on Tuesday, Jan. 7, closing schools and day care centers, grounding flights and forcing people to pull their hoods and scarves tight to protect exposed skin from nearly instant frostbite.

On this record breaking cold day, New Yorkers described the weather as "brutal." Dr. Jeffrey Rabrich at St. Luke's Hospital told Fox 5 that he has seen patients come in with frost bite. He said if you're not wearing gloves or a hat, frostbite can set in within minutes.

Central Park broke a 118-year-old record for Jan. 7 when the temperature dropped to 4 degrees. Strong winds pushed the wind chill well below zero. Central Park had a record low temp of 6° since 1896. The Tuesday temperature was 50 degrees lower than was recorded on Monday.

LaGuardia Airport in Queens also set a record low of 4 degrees. The old record of 11 degrees for Jan. 7th was set in 1968.

Cold polar vortex
© AP Photo/Charles Rex Arbogast
Cold temperatures will continue on Tuesday with a high of 10 degrees and wind chills near -10 degrees. Overnight temperatures on Tuesday night will near 5 degrees with wind chills of -10 degrees.

Amtrak stopped running trains into New Jersey out of New York's Penn Station for nearly an hour on Tuesday morning because of signal problems caused by the cold weather. Amtrak was operating a modified schedule on the Northeast Corridor between Washington and Boston, as well as the Empire Line between New York City and Albany.

Monday's subzero temperatures broke records in Chicago, which set a record for the date at minus 16, and Fort Wayne, Ind., where the mercury fell to 13 below. Records also fell in Oklahoma and Texas, and wind chills across the region were 40 below and colder. Officials in states like Indiana already struggling with high winds and more than a foot of snow urged residents to stay home if they could.

"The cold is the real killer here," Indianapolis Mayor Greg Ballard said Monday as he asked schools and businesses to remain closed another day. "In 10 minutes you could be dead without the proper clothes."

Highs in the single digits were expected in Georgia and Alabama, and wind chill warnings stretched as far south as Florida, with forecasts calling for minus 10 in Atlanta and minus 12 in Baltimore.

Forecasters said some 187 million people in all could feel the effects of the "polar vortex" by the time it spreads across the country. Tennessee utility officials braced for near-record power demand, while Ohio prepared for its coldest temperatures in decades.

More than 500 Amtrak passengers spent the night on three stopped trains headed for Chicago because of blowing and drifting snow in north-central Illinois. A spokesman said the trains - coming from Los Angeles, San Francisco and Quincy, Ill. - are operating on tracks owned by BNSF railroad and crews are working to reopen the tracks.

But there are signs things are returning to normal.

JetBlue Airways, which stopped all scheduled flights to and from New York and Boston on Monday, began resuming some flights Tuesday. Southwest Airlines operations in Chicago resumed Monday night, even if it was, as a spokesman for the Texas-based airline called it, "a trickle."

The Minnesota Zoo announced it would reopen to the public Tuesday. State lawmakers in Indiana planned to kick off their 2014 legislative session after a day's postponement.

And warmer temperatures - at least, near or above freezing - are in store for the Midwest. Indianapolis should reach 27 degrees on Wednesday, and other parts of the central U.S. could climb above freezing later in the week.

The Associated Press contributed to this report.