A once-in-a-generation winter storm sweeps through the South as much of the US deals with cold temperatures

CNN
—

About 40 million people from Texas to the Carolinas are under a winter weather alert as a rare winter storm brings bone-chilling temperatures and potentially historic snowfall to cities unaccustomed to severe cold weather.

In Texas, temperatures dropped below freezing Monday night as winter weather began across the state.

Snow flurries became more widespread in the early hours of Tuesday and could increase during the morning – with an inch per hour expected to fall, mixed with freezing rain and sleet.

The National Weather Service on Monday described the sweeping system as “a generational winter storm event,” and urged those along its path to take its impact seriously.

Travel overnight and Tuesday will be “extremely dangerous, if not impossible, for much of the area, and travel is strongly discouraged,” the service said.

The Texas snowfall is expected to shift east to New Orleans on Tuesday morning before spreading to parts of Mississippi, Alabama, Georgia, the Carolinas and the western Florida Panhandle during the day, with snowfall totals expected to break unobserved records since at least 1963 and possibly competing records from the late 1800s.

The rare winter storm comes as more than 220 million people in 40 states in the continental US are affected by bitterly cold air, with the Upper Midwest and Northern Plains likely to experience wind chill temperatures as low as minus 55 degrees.

These temperatures, if exposed to skin, can cause hypothermia in as little as 5 minutes.

Officials in affected southern states warned people to stay off roads, keep faucets dripping to prevent pipes from freezing, check batteries in smoke and carbon monoxide detectors and refrain from using stoves to heat homes.

However, these precautions are more familiar to people living in northern states rather than the south, where unusually cold conditions can strain infrastructure and resources.

“Most of us have not experienced this combination of bitter cold and significant snow ever in our lifetime,” Louisiana climatologist Jay Grymes said Monday.

Southern cities such as Houston, Atlanta, Jackson, Mississippi and Memphis, Tennessee, could also see below-freezing highs Tuesday, putting pressure on pipes that could freeze and burst.

Ahead of the winter storm, Houston Mayor John Whitmire on Sunday urged residents to protect their water pipes, noting that the city’s water system is already “fragile” with more than 1,000 active water leaks in Houston.

“Let me stress the preparation of your pipes,” Whitmire said. “Put your tubes if possible.”

Governors in Louisiana, Georgia, Alabama, Florida and Mississippi have declared states of emergency, while authorities in Texas have ordered state authorities to mobilize resources for the rare snowfall.

Arkansas has sent 12 dump trucks with snowplows to Louisiana, Louisiana Gov. Jeff Landry said Monday during a news conference on storm preparations.

“This is the time to cook a big pot of gumbo,” Landry said.

Air and road travel halted; several schools are closed

Forecasters say the Interstate 10 corridor could see possible snowfall totals of 3 to 6 inches, further crippling road travel for several days.

There were more than 1,700 flight cancellations within, into or out of the United States early Tuesday, with most of those flights coming from Texas and Louisiana, according to the flight tracking website FlightAware.

Houston’s two major airports, George Bush Intercontinental and Hobby, will close Tuesday while Hartsfield-Jackson Atlanta International Airport, the world’s busiest, prepares roadways and airfields in preparation for winter weather, according to spokesman Andrew Gobeil.

“The emergency operations center will activate at 6 a.m. Tuesday morning and will remain operational throughout the event,” Gobeil said Monday. “Passengers are encouraged to arrive at the airport at least two and a half hours before domestic departure times, unless otherwise instructed by their airlines.”

NASA’s Johnson Space Center in Houston said it will be closed Tuesday and Wednesday due to the extreme weather. Port Houston said its facilities will be closed Tuesday likewise.

Schools are closed in several states, including Georgia, Louisiana and Texas.

Gwinnett County Public Schools, the largest school district in Georgia, has moved all of its classes online. While the Houston Independent School District, the largest in the Lonestar state and the eighth largest in the nation, will also be closed until Wednesday, Whitmire said.

Several DC area schools have issued closures and delayed openings for Tuesday, including Fairfax County Public Schools – among the largest counties in Virginia.

In Florida, where schools rarely close due to winter weather, dozens of K-12 schools and state universities will close on Tuesday.

CNN’s Mary Gilbert and Lauren Mascaren contributed reporting.