(CNN) -- While snow from a massive winter storm system continued to fall Wednesday night in much of the Northeast, millions in the Midwest were left to dig themselves out yet again from even more snow and brave dangerously frigid temperatures.
An Arctic cold front followed the storm that dumped nearly 2 feet of snow in some locales, complicating cleanup efforts and spurring freeze warnings that spanned much of the nation's midsection.
In much of Wisconsin, for instance, wind chill values were expected between 20 and 25 degrees below zero Wednesday night, according to the National Weather Service.
Still, Green Bay Packers fans down in north Texas ahead of their team's Super Bowl showdown with the Pittsburgh Steelers only got a relative respite, temperature-wise. In Arlington, site of Sunday's game, there was a wind chill advisory in effect due to very cold conditions that made the temperature feel between zero and minus-10 degrees and several inches of snow and ice had a debilitating effect in parts of Dallas, Fort Worth and the surrounding area.
"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."
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Massive storm blankets US with snow The storm, though, was no laughing matter for many of the millions it has affected in recent days.
The mix of snow, sleet and freezing rain blanketed 30 states over several days, producing record-breaking accumulations in several Midwest locales, making for treacherous travel on snow-choked roadways and forcing airlines to cancel thousands of flights.
The last of the storm was drenching the Northeast late Wednesday, dumping freezing rain and snow in much of southern New England. While the amounts were less there than what some had forecast previously, the cumulative effect of relentless precipitation had a crippling impact in places.
In Massachusetts, for instance, a number of roofs collapsed under the weight of rain-soaked snow, including the roof of a large commercial building in the town of Easton, according to fire captain David Beals. Up to 100 employees were evacuated prior to the collapse, he said. No injuries were reported.
This appeared to be the last breath of a massive system that, at one point Monday night, prompted the National Weather Service to issue winter storm warnings, watches or advisories in at least 29 states in a 2,000-mile space stretching from the Southwest to the Northeast.
The huge demand for information caused sporadic outages for the 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 experiences an average of 70 million hits per day.
Chicago was hit hard, too, in a different way.
O'Hare International Airport received a record-breaking 20.2 inches of snow, according to the weather service. The Windy city at times crippled by the combination of gusts and blinding precipitation.
Raymond Roscoe, chief of staff for Chicago Mayor Richard Daley, said many motorists remained stuck in their cars throughout the night, while others abandoned their vehicles. Police, fire department and sanitation crews spent much of the night pulling people out of their cars, he said. Roscoe said there were no reports of injuries.
"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 theater."
The good news was that the blizzard warnings for northeastern Illinois, including the Chicago metropolitan area, were called off. Still, even as the snow tapered off, forecasters said wind chills may fall to 20 to 40 degrees below zero late Wednesday.
"The wind on the lake shore is beyond belief," said Chicago resident Anni Glissman. "It almost knocks you over."
Elsewhere, Illinois State Police carried out a rescue operation in Kankakee County after 20 cars were stranded in the snowstorm, where snowdrifts were measured at about 3 feet, the agency said.
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The rescued motorists were taken to temporary warming centers in Manteno or Peotone, said state police Sgt. Angie Kinstner.
In Wisconsin, the Department of Transportation reported that Interstate 42 and Interstate 94 were impassable south of Milwaukee. The National Guard was making a sweep of the interstates for stranded motorists.
Oklahoma Gov. Mary Fallin asked federal authorities Wednesday to approve an emergency disaster declaration for all the state's 77 counties, a move that would expedite post-storm assistance, according to a release from the state's Department of Emergency Management. Fallin had declared a state of emergency on Monday in advance of the storm.
A 20-year-old Moore, Oklahoma, woman died while after her hitting her head while sledding during the storm, the statement said. Many others were injured in Oklahoma -- 77 in falls, four in carbon monoxide poisonings, 13 with cuts, 24 in road accidents, two with frostbite and five in other storm-related injuries, according to the state health department.
In addition, the state highway patrol responded to 81 storm-related crashes and 278 calls from motorists seeking help.
Air travel was just as difficult across the region. O'Hare was expected to have limited or no flight operations on Wednesday, said Karen Pride, a spokeswoman for the Chicago Department of Aviation. More than 2,200 flights were canceled. At Chicago's Midway Airport, airlines canceled most flight operations on Tuesday.
Nationwide, airlines canceled more than 4,000 flights Tuesday, with thousands more grounded on Wednesday. Delta Air Lines announced the cancellation of 1,175 Delta and Delta Connection flights for Wednesday.
In Boston, 496 flights were canceled at Logan International Airport, said Phil Orlandella, a spokesman for Massport, which manages the airport. The airport's two runways were temporarily closed while a deicing treatment was applied, Orlandella explained.
Jet Blue canceled all its flights out of Logan for the day.
In Philadelphia, 221 flights had been canceled by 6:45 a.m., said Victoria Lupica, an airport spokeswoman.
More than 1,000 flights were canceled at New York's JFK International Airport and La Guardia, and New Jersey's Newark Liberty International, according to Port Authority spokeswoman Sarah Joren. Continental Airlines said it was suspending all operations at Newark's airport through noon Wednesday.
Further afield, the lingering affects of the large system brought needed rain to much of the South on Tuesday, but also unwelcome ice and hard freeze warnings, which remained in place on Wednesday in most of eastern Texas and southwestern Louisiana.
"If you're traveling your certainly going to have troubles," said National Weather Service forecaster Bruce Sullivan. "Tomorrow we're looking at potential icy conditions across the Gulf states."
Rolling power outages swept across Texas on Wednesday as a result of the blustery weather, officials said.
"Because of winter weather conditions that have created an unprecedented demand on the state's energy grid, many Texans across our state are experiencing power outages today," said Texas Governor Rick Perry in a written statement. "I urge businesses and residents to conserve electricity to minimize the impact of this event."
The Public Utility Commission of Texas said rotating outages would be limited to 10 to 45 minutes, unless equipment fails due to a power surge during the restoration process, according to the statement. Fifty power plants were out statewide due to the extreme weather, leading to the 10%-15% reduction in electricity production, said utility commission spokesman Terry Hadley.
The National Weather Service issued a winter storm watch effective Thursday afternoon through Friday morning for southeastern Texas, including the Houston metropolitan area.
Snow, sleet and freezing rain is possible across the metro area, the service said, while forecasters say accumulations of 1 to 3 inches are expected to create hazardous road conditions.
High-wind warnings were posted Wednesday in the mountains of western North Carolina and Virginia, with gusts as high as 50 mph forecast in Boone, North Carolina.
Up to an inch of freezing rain plagued travelers in Columbus, Ohio, causing slippery road conditions across much of the state, forecasters said.
Plummeting temperatures were expected to filter in behind the system, dropping to below zero in the upper Plains states over the next few days. Parts of the Texas Panhandle and western Oklahoma also will experience some of the coldest air this season, CNN meteorologist Sean Morris said.
Will Rogers World Airport in Oklahoma City doubled its previous record snowfall Tuesday, receiving 11.8 inches, while emergency personnel warned of frigid weather conditions that could reach temperatures of minus-15 degrees on Wednesday.
Smack in the middle of the storm track is Punxsutawney, Pennsylvania, home of a certain groundhog, who has been forecasting the end of winter for more than 100 years. When Phil emerged from his hideout early Wednesday, he saw no shadow -- meaning, according to tradition, that spring will come early this year.
By the time the snow stopped falling Wednesday, the total snowfall recorded at O'Hare International Airport reached 20.2 inches, putting the storm third behind historic winter snows of 1967 and 1999.
If this storm was different from the other two, it was because weather scientists had seen it coming days in advance.
"We did pretty damn well," said Mark Ratzer, a meteorologist at the National Weather Service in Chicago. "Our forecast all along for Chicago had been around 20 inches and that's essentially what we ended up with, which was right in the ballpark given the magnitude of the storm."
It was a remarkably accurate forecast given the size and complexity of a fast-moving storm that flared up Friday off the coast of California. Meteorologists expected that moist air from the Pacific and Gulf Coast would give the storm heft and volume, and therefore knew that the system could bring blizzardlike conditions to the Chicago area.
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By Monday, scientists had determined there was a 75 percent chance that Chicago would see at least a foot of snow overnight and that wind gusts would top 50 mph.
They also had correctly predicted the possibility of what's commonly called "thundersnow," an unusual meteorological phenomenon in which intense thunder and lightning accompany a snowstorm. At the peak of the storm's fury, lightning was hitting the ground as many as 50 times in one hour, Ratzer said.
Thundersnow occurs when warm, moist air circulates vertically with the cold temperatures of a winter storm below, experts said. On Tuesday night, thunder and lightning added an eerie element to the wind-whipped snowstorm.
"Thundersnow generally doesn't last very long and it looks pretty weird because it's snowing and your visibility is limited and the whole sky lights up green," Ratzer said. "I don't recall seeing a storm, in my 16 years I've been doing this, that produced as much thunder and lightning as this one."
The storm's severity varied slightly throughout the area. Hardest hit were lakefront North Side neighborhoods and North Shore suburbs, where at one point snow was falling at 3 to 4 inches an hour. Areas near the lake also took on a couple of extra inches of lake-effect snow.
Meteorologists were able to forecast this storm so precisely because of advancements in computer modeling technology, as well as improvements in data collection and observation, said John Ferree, a severe storm expert at the National Weather Service in Oklahoma.
Computer models are now able to calculate up to 20 different scenarios of a storm's impact and then select the average, or the most likely that is to occur based on ever-changing weather conditions. This modeling software has been used for only about five years and factors in the inherent uncertainties about a storm's behavior.
The computer programs are also able to take in other variables, such as the atmospheric profiles of temperatures, moisture and winds taken throughout the country by surface observation, weather balloons, satellites, commercial airlines and advanced weather instruments on weather service aircraft.
"We have better training, better tools, better communication and it all adds up to a better forecast," Ferree said. "As a forecast of a major event, this one turned out pretty good."
Which makes Thursday's forecast of extended subzero temperatures and extreme wind-chill warnings of 20 below zero all the more chilling.