Snow, ice and bitter cold are hitting Southern states unaccustomed to such frosty conditions.
More than 80 million people are under winter storm warnings or advisories in states stretching from Texas to Maine, with snow -- or a wintry mix of snow, sleet and freezing rain -- expected in parts of the South, according to the National Weather Service.
In south Houston one homeless person died from hypothermia, fire Chief Samuel Peña said.
Drivers in the city were dealing with difficult conditions.
Police had responded to 278 crashes as of Tuesday evening, 104 of which were major, said Houston Police Chief Art Acevedo.
The icy mess was thwarting pilots, too.
There were almost 1,000 flight cancellations at the two major Houston airports Tuesday because of severe weather, said Frank Ciaccio, emergency management coordinator for the Houston Airport System.
Most of those flights were at George Bush Intercontinental Airport, Ciaccio told reporters.
The severe weather has also left more than 8,000 homes and businesses without power.
Wide swath of precipitation
The main swath of snow, generally 2 to 6 inches, was expected to drop from far northeast Texas and into parts of Arkansas, eastern Mississippi, western Tennessee, Kentucky and West Virginia, forecasters said.
The system is expected to exit southeast Texas and push through the South from Louisiana to Georgia, bringing 1 to 2 inches in portions of those states. It will move across the Carolinas during overnight and morning hours Wednesday, ending in the Coastal Plain by late afternoon.
By late morning Tuesday, 6 inches had already fallen in parts of eastern Arkansas and Kentucky, and portions of Tennessee received as much as 4 inches, the National Weather Service said.
In Memphis, the NBA's Grizzlies canceled practice, citing the weather there. Area resident Jeanne Suratt told CNN affiliate WATN ahead of the storm that she'd be staying put in her home.
"I've already been to the grocery store to try to get the necessary things that we will need for the next two or three days. We will not be out of the house," Suratt said.
Some school systems closed, including in St. Louis, where the main concern was below-zero wind chills, and Nashville, which faced several inches of snow as well as below-zero wind chills.
Also closed was the University of North Alabama, where a dusting of snow had collected by midmorning. A junior there, Nick Saunders, said he was "just excited to have a break from class for a day."
"A pleasant surprise to wake up to," he wrote with a video of the snow that he posted on Instagram.
On Monday, Alabama Gov. Kay Ivey declared a state of emergency in expectation of snow, sleet and freezing rain.
"There are enough uncertainties in the forecast right now that the potential exists that this winter storm could be debilitating to the state for a couple of days due to icy conditions," Brian Hastings, director of Alabama Emergency Management Agency, said in a statement.
Snow should fall into Wednesday in parts of the Northeast, including southern New York and Massachusetts, which could see up to 8 inches.
In addition to the snow, more than 40 million people are under wind chill alerts from the northern Plains, such as western Montana, North Dakota and Minnesota, down to portions of Texas and Louisiana. With the wind chill, temperatures could feel as low as minus 40 degrees in the more northern states.
Freezing rain, ice in Texas, Louisiana
Freezing rain fell in the San Antonio and Austin areas of Texas. A light glaze of ice and several car wrecks were reported in San Antonio, according to CNN affiliate KSAT.
Southern Texas and Louisiana could see ice accumulate up to a quarter inch, according to CNN Weather.