Snow fell Monday night in the Houston area and more than 55 million people could be affected by a historic winter storm that is expected to bring rare snow and frigid temperatures to the entire Gulf Coast by midweek, forecasters said.

Monday night, the storm will bring ice and snow to Houston; Baton Rouge, Louisiana; and other cities across the South.

Houston's two main airports, George Bush Intercontinental and Hobby, said they would suspend flight operations starting at midnight Tuesday.

Louisiana Gov. Jeff Landry warned Monday that people should stay home and remember to prevent pipes from freezing.

"It's very important to stay off the roads," he told a news conference. "Unless you absolutely need to be on the road, please stay home and stay warm."

Forecasts show up to 4 inches of snow in most areas, but up to 6 inches in parts of Texas and Louisiana.

The National Weather Service office in Houston said Monday night that sleet and light snow were reported as far south as the Interstate 10 corridor through the Texas city.

Moderate snow is expected Tuesday along Interstate 10 from New Orleans to the Florida Panhandle, with widespread ice in Tallahassee and Jacksonville, Florida.

National forecasters say the winter storm could severely impact the Gulf Coast, where most cities are without snowplows.

The Louisiana Department of Transportation and Development said 400,000 pounds of salt have been accumulated and can be spread on roads and bridges if needed to deal with the ice and snow, and officials are working on a plan for possible road closures.

Temperatures will be below freezing in Louisiana, with temperatures in the teens early Tuesday in New Orleans and other parts of the state, the National Weather Service said. The agency said wind chills in southwest Mississippi could reach 6 to 9 degrees on Wednesday.

Forecasters said freezing rain was possible as far north as coastal Georgia, South Carolina and North Carolina.

Snow and heavy rain will affect the Florida Peninsula along the Atlantic coast later this week.

Cold warnings were in effect for 214 million people on Monday from the Rockies to southern Texas and central Florida, with temperatures 20 to 40 degrees below average, forecasters said.

Officials said some areas along the South and Gulf Coast will experience more than 24 hours of subfreezing temperatures, which could lead to infrastructure issues such as widespread pipe bursts.

Wind chills will cause temperatures to reach -55 degrees in the Rockies, Northern Plains and parts of the upper Midwest.

Sub-zero wind chills will affect the Northeast on Tuesday and Wednesday.

Finally, cold records could be set in Missouri, Texas, Louisiana and Alabama.