(CNN) -- A swirl of sleet and freezing rain barreled into the Gulf States Thursday, yet another winter storm carrying frigid weather to a region unaccustomed to the cold.
The storm system extended from Corpus Christi, Texas, through Louisiana, Mississippi and most of central Alabama, as forecasters predicted up to 5 inches of snow in scattered areas across the Deep South and along the U.S.-Mexico border.
Ice and snow accumulation on roads and bridges is expected to make travel dangerous, if not impossible, in some places through Thursday night and into Friday morning, forecasters said. A winter storm warning remains in effect until midday Friday for all of far south Texas.
Forecasters predicted a wintry mix of snow and sleet would coat downtown Houston with about an inch of accumulation.
Heavier snowfall -- up to 3 inches -- will blanket areas west of the city.
In New Orleans, forecasters predicted mostly rain with a sleet mix in the city's northern districts and outlying neighborhoods.
Louisiana Gov. Bobby Jindal declared a state of emergency Thursday in anticipation of the weather, activating the state's Crisis Action Team to monitor possible hazardous conditions that could affect parts of the state over the next few days.
State government offices in 55 Louisiana parishes will be closed on Friday because of the wintry weather.
Southwest Airlines canceled all flights to Corpus Christi, Harlingen, and Houston Hobby airports in Texas, according to company spokesman Marilee McInnis. The carrier called off a total of 157 flights on Thursday, she said.
Light snow accumulations ranging from less than an inch of snowfall in Dallas to heavier amounts to the south and east raised questions as to whether inclement weather would impede Super Bowl travelers.
Green Bay Packers fans in north Texas ahead of their team's showdown with the Pittsburgh Steelers got only a relative respite, temperature-wise, from what they usually experience up in Wisconsin.
In Arlington, Texas, site of Sunday's game, a wind-chill advisory was in effect due to very cold conditions that made the temperature feel between zero and 10 degrees below, and several inches of snow and ice had a debilitating effect in parts of Dallas, Fort Worth and surrounding areas.
"It was funny to see a whole city shut down. Everything was closed," said Packers' defensive lineman Ryan Pickett. "In Green Bay, this is just a normal day."
But weather conditions for the big game are expected to be sunny, though chilly, with a high of 45 degrees, forecasters said.
Continental Airlines said it suspended most of its operations from Houston Intercontinental Airport from Thursday afternoon through midday Friday because of the expected icy precipitation.
Houston pre-emptively decided schools will be closed Friday due to forecasts of 2 to 5 inches of snow, according to school district spokesperson Sarah Greer Osborne.
The extreme weather has put unprecedented demand on the state's energy grid and put 50 power plants out of commission on Wednesday, leading to rotating outages and a 10% to 15% reduction in output. By Thursday, most of the plants had resumed functioning, said Terry Hadley, the state's utility commission spokesman.
The storm hit the Deep South as a previous storm system swirled out of the country after blanketing 30 states, from the center of the nation through the Northeast, with a mix of snow, sleet and freezing rain producing record-breaking accumulations in several Midwest locales.
The severe weather sparked a huge demand for online information, causing sporadic outages for the National Weather Service's web servers, which struggled to handle a deluge of 10 million to 20 million hits per hour, officials said. The site normally gets 70 million hits per day.
The storm system dished perhaps the hardest blow to Chicago, where temperatures hovered around 3 degrees Thursday.
O'Hare International Airport received 20.2 inches of snow, adding to the city's third-largest snowstorm on record, according to the Weather Service.
Shannen Park, who spent Tuesday night camped out at the Chicago airport, endured multiple cancellations, like many travelers stranded by the blustery weather.
"Geez, I'm getting home finally," Park said, as some flights resumed Thursday.
Chicago resident Guy Zalel said he "knew leaving Monday that the flights would be pretty bad."
But the frigid weather didn't stop Diane Buckner, a Chicago resident and self-proclaimed "hot-blooded Latin woman" from donning a feathered cabaret headdress and bikini and posing for photographs with her fellow Chicagoans.
"I took advantage of it and did something daring and outside of the box to promote my business and dance troupe," Buckner said. "This was my attempt to bring some laughs to a not-so-funny situation."
More than 1,100 flights were canceled Thursday at O'Hare, while some 40 flights were called off at Midway airport due to the lingering effects of the storm.
Airport authorities encouraged travelers to check their airline's website or call ahead to check the status of their flights before going to the airport, said Gregg Cunningham, a spokesman for the Chicago Aviation Department.
Raymond Roscoe, chief of staff for Chicago Mayor Richard Daley, said that many motorists were stranded in their cars when the storm hit, while others abandoned their vehicles.
"There were no cars or people on the street and you couldn't see the buildings nearby because of the thick snow," said city resident Sruthi Swaminathan. "The only thing you could see clearly were the lights from the Chicago Theatre."
Public schools are expected to reopen Friday, Daley said.
In Oklahoma, a sport utility vehicle skidded off a bridge and plunged 80 feet into a river along Interstate 44, killing at least three people, according to police spokesman George Brown.
Five medical evacuation helicopters and emergency dive teams responded to extract the eight people involved in the accident near Miami, Oklahoma. Five surviving men were taken to a level two trauma facility at St. John Medical Center in Tulsa, where they were treated for hypothermia.
A 20-year-old woman died Tuesday following a sledding accident in Moore, Oklahoma, emergency management spokeswoman Michelann Ooten said in a written statement.
State police have responded to 139 storm-related vehicle crashes, Ooten said, while some government offices, schools and businesses remained closed Thursday due hazardous road conditions,
Most Chicago-bound flights from Will Rogers World Airport in Oklahoma City were canceled Thursday, according to Oklahoma City Department of Airports spokesman Karen Carney, who added cancellations and delays at other airports also were likely to affect travelers from Oklahoma.
"It appears that it will take several days, or longer, for flights to return to normal," Carney said in a news release. "The airport continues to advise travelers to check with the airline for their flight status prior to coming to the airport."
In South Dakota, officials closed a 90-mile stretch of Interstate 29 from Watertown to the North Dakota border due to blizzard conditions, said state authorities, who reported numerous accidents and whiteout conditions along the highway.
The backside of the historic weather system was still powerful enough to drop several more inches of snow on Maine and New Hampshire on Thursday, the National Weather Service said.
The Arctic cold front complicated cleanup efforts and spurred hazardous weather outlooks that spanned much of the nation's heartland.
CNN's Dave Alsup and Chris Welch contributed to this report.