There were at least 15 weather-related fatalities: 11 in Tennessee, three in Ohio and one in Kentucky. More than half of the deaths in Tennessee were due to hypothermia, while one was a dialysis patient unable to get to medical care. The rest were involved in car accidents.
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The blast of blisteringly cold air that some forecasters call the Siberian Express broke temperature records on Thursday.
"Our city just shuts down," Dana Marie, a waitress in Nashville, Tennessee, which bottomed out at 4 F, told TODAY. "You know, people in the North want to make fun. And I get it. It's just that we're not used to it."
Nashville was relatively well off. An hour outside town, in Clarksville, it was -7 F. The low in Round Springs, Missouri, was -21 F. Cincinnati, Detroit and Louisville, Kentucky, were all below zero and set records for the coldest Feb. 19.
Chicago broke a 79-year-old record: The air temperature at O'Hare International Airport dropped to minus 8 degrees around 6 a.m. — inching ahead of the -7 F recorded on Feb. 19, 1936, NBC Chicago reported.
Lexington, Kentucky, checked in at -7 F, the coldest on any day since January 2003. Bowling Green also hit 7 below, the coldest there since January 1994. In the town of Embarrass, Minnesota: -41 F.
In Florida, where baseball teams began trickling in for training camp, the forecast high for Orlando was an unusually chilly 51. Miami was only expected to reach 58.
Tempers also flared in cities besieged by an ongoing onslaught of winter weather. In Boston, a fight broke out Wednesday night on a commuter rail train, NBC station WHDH reported.
"The weather has caused all the disruptions, I get it. But by no means does that give anybody an excuse to be combative or assaultive to another person," said Interim Transit Police Chief Kenneth Green.
Meanwhile, nearly 40 passengers on a Greyhound bus traveling Thursday from Minneapolis to Chicago endured hours of cold after the heater apparently went out, NBC Chicago reported.
More bad weather is on the way. The Weather Channel said record lows could be set Friday morning in six dozen communities from New England to Florida, with single digits possible as far south as Georgia, North Carolina and Tennessee.
And the next winter storm isn't far behind. It should begin on Friday in Arkansas, Tennessee, Missouri and Kentucky, changing to rain by Saturday. The Great Lakes and the interior Northeast could get heavy snow.
Boston got another half-inch of snow on Wednesday and moved to within 11 inches of its all-time snowiest winter, 107.6 inches in 1995-96. The transit system has been crippled there by a relentless series of snowstorms.
A little more snow is likely in Boston on Saturday night, and there could be another snowstorm in the middle of next week.
—NBC News' Miranda Leitsinger contributed to this report.