By Tuesday night there was a long line of precipitation that brought 2 inches of snow to some areas of Mississippi, 6 inches in Kentucky and 4 inches in Vermont.
"Accumulating snowfall will bring travel implications from the southeast US to the Middle Atlantic, Northeast, and New England through Wednesday," the National Weather Service said.
In Houston the cold accompanying the storm was deadly. 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.
Super cold temps
Forecasters said the "very cold" temperatures would hang around until Thursday, meaning people in the Deep South and other areas would have to pull out their heaviest coats, dress in lots of layers, or stay inside.
Some school districts, like those in Atlanta where light snow was falling, announced they wouldn't open Wednesday.
In Louisiana, Interstate-10 from Baton Rouge to Lafayette was closed.
"The rapidly freezing temperatures has caused this stretch to be deemed impassable for motorists," the Louisiana Department of Transportation and Development said. Parts of Interstate-49 were also closed.
The wind chill index in some parts of the state were already in the single digits.
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
Some areas were still to see the harshest conditions overnight. In New York meteorologists said steady snow will fall overnight. CNN affiliate WABC said Wednesday morning's commute will be slick but conditions will improve when temperatures break the freezing mark.
In Atlanta, it was supposed to be 16 degrees for the low Wednesday but winds were going to be 15 mph or stronger, making for a wind chill of zero.
City offices were shuttered for Wednesday and Georgia Gov. Nathan Deal declared a state of emergency for 83 counties in the northern and central sections of the state.