Blizzard conditions and heavy snow blasted the Gulf Coast on Tuesday as a massive winter storm struck the South.A winter storm warning is in effect along the Gulf Coast from South Texas all the way to Florida. There are also winter storm warnings in Georgia, South Carolina, and North Carolina.Meanwhile, nearly 250 million Americans are under cold weather advisories or extreme cold warnings. Temperatures that are 20 to 30 degrees below normal are commonplace for most of the U.S. on Tuesday.RELATED STORY | Experts: Why the cold weather does play a role in catching coldsThe National Weather Service said it issued its first-ever blizzard warnings for Jefferson and Orange counties in Texas, as well as Cameron, Calcasieu, Jeff Davis, Acadia, Vermilion, and Lafayette parishes in Louisiana. Heavy snow combined with winds topping 35 mph is expected for the region. The blizzard warning was dropped by Tuesday afternoon, but roads remained snow-covered as the advisory ended.Tuesday's storm also marked the first time that a blizzard warning has been issued anywhere in the state of Louisiana.Airports DisruptedNearly all flights in and out of Louis Armstrong New Orleans International Airport, Houston's George Bush Intercontinental Airport, and Houston's William P. Hobby Airport are canceled today. San Antonio International Airport also experienced a sizable number of cancellations.Most major airlines are offering travel waivers, making it easier for passengers to rebook their flights for another day.Highways SnarledSections of Interstates 10, 45, and 69 were closed on Tuesday in and around the Houston area. Additionally, Interstate 10 in both the eastbound and westbound directions from Interstate 49 to La. 415 was closed on Tuesday amid blizzard-like conditions.Officials also closed the Lake Pontchartrain Causeway Bridge north of New Orleans due to ice buildup.Forecasts indicate that most of the Deep South should rise above freezing on Wednesday, but it might be early next week before temperatures return to near normal.