An unprecedented winter storm is crippling the Gulf Coast with heavy snow and ice

A big winter storm struck the southern United States Tuesday covered parts of the Gulf Coast with record snowfall in a region largely unaccustomed to extreme winter weather.

The storm, battering areas from Texas to Florida and up the Carolina coast, has led to widespread closures and escalating travel disruptions Wednesday, including stranded motorists and delayed flights. Airports in Louisiana, Mississippi and Florida closed Tuesday due to unprecedented snowfall.

The National Weather Service in Mobile, Alabama, urged residents on social media Tuesday to “keep off the roads tonight,” warning of “treacherous, life-threatening conditions.” Major cities along the East Coast as far south as Jacksonville, Fla., are expected to experience snow, sleet and ice accumulation through Wednesday, potentially forcing closures of schools and government offices.

In Georgia, cities like Atlanta, Macon and Augusta are bracing for potential ice buildup from melting snow refreezing on roads. Governor Brian Kemp warned residents that conditions “could get worse very quickly,” reminiscent of an infamous 2014 gridlock that left millions in Georgia stranded on the roads.

More than 25 million people are under winter weather warnings from Florida to Virginia early Wednesday — all while much of the central and eastern United States is experiencing temperatures running 20-30 degrees below average.

Here are the latest developments:

Snowfall records broken

New Orleans broke its modern record for all-time daily snowfall on Tuesday, receiving 8 inches of snow, far surpassing the previous record of 2.7 inches. The city has recorded more snowfall this month than Anchorage, Alaska, which saw nearly two inches in January.

Other southern cities also broke long-standing snowfall records:

• Mobile, Alabama, reported 7.5 inches, surpassing the previous record of 3.6 inches set in 1973.

• Pensacola, Florida, recorded 7.6 inches, surpassing its 1954 record of 2.3 inches.

• Milton, Fla., had a preliminary total of 8.8 inches, potentially breaking the state snow record.

Widespread roadblocks

With cold weather conditions across the region this week, roads could remain dangerous as the snow melts and refreezes.

In Louisiana, Interstate 10 from the Louisiana/Texas state line to Baton Rouge — a stretch of about 150 miles — was closed in both directions due to “deteriorating road conditions” Wednesday morning, according to the state Department of Transportation and Development. Nearly 30 state roads were closed as of Tuesday, including the Lake Pontchartrain Causeway — the nation’s longest bridge over water.

To help treat roads, New Orleans has hired 14 snowplows from an Indiana-based company, city Director of Homeland Security and Emergency Preparedness Collin Arnold told reporters Tuesday. The initial focus will be on clearing critical routes, while crews will tackle main thoroughfares, he said.

Meanwhile, roads in Alabama Escambia, Mobile and Baldwin Counties were deemed “impassable” and closed due to the storm’s impact, officials said.

Nineteen counties in Mississippi still reported ice on roads and bridges at 9 p.m. local time Tuesday, with black ice remaining a significant threat into the night, Mississippi Department of Transportation said on social media. “Authorities recommend that only emergency travel be advised in the affected areas.”

In Georgia, state officials held a news conference Tuesday warning residents to stay off roads, especially those covered in new snow, as conditions are ripe for melting and immediate refreezing. The Georgia Department of Transportation has treated over 43,000 lane miles with 1.7 million gallons of brine to mitigate ice buildup, officials said.

Airport disturbances

More than 1,200 flights have been canceled nationwide as of Wednesday morning, primarily affecting routes to and from Texas and Louisiana, according to FlightAware.

Key closures include both of Houston’s major airports — George Bush Intercontinental and Hobby — as well as Louis Armstrong New Orleans International Airport, where all flights have been canceled and operations are expected to resume Wednesday. Lafayette Regional Airport in Louisiana is also closed due to icy conditions.

In Mississippi, Gulfport-Biloxi International Airport has closed its terminal and runway until conditions improve. Airports in Mobile, Tallahassee and Jacksonville shut down and aim to reopen by noon Wednesday.

Deadly relations

Nationwide, at least nine deaths have been reported due to the severe cold that is affecting large parts of the country. On Tuesday, at least five people died in a car crash caused by icy conditions in Zavala County, Texas. according to CNN affiliate WOAI/KABB, citing authorities.

In addition, authorities are investigating two deaths in Austin as potential cold-related deaths, although the medical examiner’s office has not confirmed the causes. In Georgia, officials reported a hypothermia-related death, noting that the person had been outside the previous night.

While the winter storm has had a visceral impact on the Gulf region, sub-freezing temperatures are also affecting large parts of the United States. An 80-year-old Milwaukee man is suspected of having died of hypothermia after falling outdoors early Sunday, according to the Milwaukee County Medical Examiner’s Office.

As temperatures dipped below freezing this week, the plight of those experiencing homelessness became increasingly dire.

In San Antonio, Mariah Pena and Daniel Vertiz felt the weight of this reality when Pena found a woman taking refuge in their front porch dog kennel on Sunday, CNN affiliate KSAT reported. Frightened, yet desperate, the woman explained that she had nowhere else to turn.

Although the couple hesitated to invite a stranger into their home, they felt compelled to help, believing that even a temporary shelter would provide respite from the life-threatening cold. “Who knows what might have happened if she was left on the street?” Vertiz told the magazine.

Forecast ahead

As the snowfall slows, officials warn that any melting snow from Tuesday will refreeze as temperatures drop.

In the greater Houston area, temperatures dipped into the mid-20s, with forecasters predicting a drop to as low as 18 degrees overnight. An extreme cold warning remains in effect until 10 a.m. ET Wednesday, with chills that will make it feel as cold as 10 degrees. The highest accumulation in the greater Houston area was reported three miles southeast of the city, where 4.0 inches fell.

The National Weather Service in Houston warned that “wet, slippery roads will be deadly tonight” and urged residents to avoid travel unless absolutely necessary. The Houston Office of Emergency Management has repeated this message through several warnings, advising residents to stay off the roads until Wednesday morning.

While temperatures are expected to rise above freezing on Wednesday, the forecast warns of another overnight freeze on Thursday morning, which could again lead to dangerous road conditions.

Widespread snowfall totals across the Carolinas and Virginia could reach 2-6 inches with isolated totals potentially reaching 8 inches. Across Georgia and Florida, snowfall totals of 2-4 inches are possible along with ice up to a quarter inch. The bulk of the snowfall will end across the Carolinas and Virginia by Wednesday morning.

CNN’s Mary Gilbert, Brandon Miller, Alexandra Skores, Lauren Mascarenhas, Jamiel Lynch, Karina Tsui and Dakin Andone contributed to this report.

For more CNN news and newsletters create an account at CNN.com