Tens of millions of people stayed home. The hardy few who ventured out faced howling winds that turned snowflakes into face-stinging needles. Chicago's 20.2 inches of snow was the city's third-largest amount on record. In New York's Central Park, the pathways resembled skating rinks.
The storm that resulted from two clashing air masses was, if not unprecedented, extraordinarily rare for its size and ferocious strength.
"A storm that produces a swath of 20-inch snow is really something we'd see once every 50 years - maybe," National Weather Service meteorologist Thomas Spriggs said.
Across the storm's path, lonely commuters struggled against drifts 3 and 4 feet deep in eerily silent streets, some of which had not seen a plow's blade since the snow started a day earlier. Parkas and ski goggles normally reserved for the slopes became essential for getting to work.
"This is probably the most snow I've seen in the last 34 years," joked 34-year-old Chicagoan Michael George. "I saw some people cross-country skiing on my way to the train. It was pretty wild."
Although skies were beginning to clear by mid-afternoon over much of the nation's midsection, the storm promised to leave a blast of bitter cold in its wake. Overnight temperatures in the upper Midwest were expected to fall to minus 5 to minus 20, with wind chills as low as minus 30.
The system was blamed for the deaths of at least a dozen people, including a homeless man who burned to death on New York's Long Island as he tried to light cans of cooking fuel and a woman in Oklahoma City who was killed while being pulled behind a truck on a sled that hit a guard rail.
Airport operations slowed to a crawl nationwide, and flight cancellations reached 13,000 for the week, making this system the most disruptive so far this winter. A massive post-Christmas blizzard led to about 10,000 cancellations.
In the winter-weary Northeast, thick ice collapsed several structures, including a gas station canopy on Long Island and an airplane hangar and garages near Boston. In at least two places, workers heard the structures beginning to crack and narrowly escaped.
In Middletown, Conn., the entire third floor of a building failed, littering the street with bricks and snapping two trees. Acting Fire Marshal Al Santostefano said two workers fled when they heard a cracking sound.
"It's like a bomb scene," Santostefano said. "Thank God they left the building when they did."
More than a half-dozen states began digging out from up to a foot of snow that made roads treacherous and left hundreds of thousands of homes without power.
Chicago public schools canceled classes for a second straight day. And the city's iconic Lake Shore Drive remained shut down, nearly a day after drivers abandoned hundreds of snowbound vehicles.
The famous freeway appeared as if rush hour had been stopped in time, with three lanes of cars cluttering the pavement amid snow drifts that stood as high as the windshields. Bulldozers worked to clear the snow from around the cars, which were then plucked out by tow trucks one by one.
As the storm built to full strength Tuesday evening, 26-year-old Lindsey Wilson sat for hours on a stranded city bus. She eventually joined other passengers who tried to walk home. She made it about 100 feet before she couldn't see anything around her, including the bus she'd just left.
Fearing she would be swallowed by mounting snow drifts, Wilson turned back and spent the night on the bus.
"I thought if I fall over, what would happen if I got buried under a pile of snow?" she said.
Some motorists came away angry, frustrated that city didn't close the crucial thoroughfare earlier. Others were mad at themselves for going out during the storm or not using another route.
"In 31 years with the city, I haven't experienced anything like we did at Lake Shore Drive," said Raymond Orozco, chief of staff for Mayor Richard M. Daley. "Hundreds of people were very inconvenienced, and we apologize for that."
Orozco took responsibility for the decision not to close the drive as soon as snow began to fall Tuesday, but insisted he stood by the choice. He also hinted that his boss wasn't satisfied.
"I think the mayor knows we can always do better," Orozco said.
At dusk Wednesday, more than 200 cars remained on the drive, and city workers planned to work through the night to remove them. But it wasn't clear whether the job would be done in time for the morning rush.
Elsewhere, utility crews raced to restore power to tens of thousands of homes and businesses in Ohio, New Jersey and Pennsylvania, where freezing rain and ice brought down electrical lines.
Rolling blackouts were implemented across Texas, including in Super Bowl host city Dallas, due to high demand during a rare ice storm. The outages would not affect Cowboys Stadium in suburban Arlington, said Jeamy Molina, a spokeswoman for utility provider Oncor. But other Super Bowl facilities, such as team hotels, were not exempt, she said.
The storm derived its power from the collision of cold air sweeping down from Canada and warm, moist air coming up from the south.
"The atmosphere doesn't like that contrast in temperature. Things get mixed together and you have a storm like this," said Gino Izzo, another weather service meteorologist. "The jet stream up in the atmosphere was like the engine and the warm air was the fuel."
The contrasts were most dramatic in Texas earlier in the week, when one part of the state reported temperatures in the single digits and another part had temperatures in the 70s, with near-tropical humidity.
"That was the breeding ground for this storm," Izzo said.
Louis Uccellini, director of the government's National Centers for Environmental Prediction, said the storm also drew strength from the La Nina (la NEEN'-ya) condition currently affecting the tropical Pacific Ocean.
La Nina is a periodic cooling of the surface temperatures of the tropical Pacific Ocean, the opposite of the better-known El Nino (el NEEN'-yoh) warming. Both can have significant impacts on weather around the world by changing the movement of winds and high and low pressure systems.
Still, some people in the storm's wake shrugged off the weather - and nearly the whole season.
"It's winter. It should have snow and ice. It's the way it is," said Vincent Zuza of Chatham, N.J., who was waiting for a flight to Salt Lake City for a ski trip after his first flight was canceled Wednesday. "You can't get too upset about it, and you can't control it. You just have to make the best of it."
For some of those battered by the storm, there was one whimsical ray of hope: The world's most famous weather forecaster - with four legs - predicted an early spring.
Punxsutawney Phil's handlers told Groundhog Day revelers at Gobbler's Knob, a tiny hill in Punxsutawney, Pa., that the groundhog had not seen his shadow, meaning winter will end within six weeks, according to tradition.
Associated Press writers Deanna Bellandi, Karen Hawkins, and Barbara Rodriguez and photographer Kii Sato in Chicago; Jim Salter in St. Louis; Patrick Walters in Philadelphia; Ula Ilnytzky in New York City and Adam Pemble in Newark, N.J., contributed to this report.