The Day After Tomorrow

The movie opens with Jack Hall in Antarctica with two colleagues, Frank and Jason, drilling for ice core samples on the Larsen Ice Shelf for NOAA. The ice shelf cracks and breaks off from the rest of the continent, nearly killing Jack. He travels to a United Nations conference held in Islamabad, Pakistan on global warming. Diplomats from several countries, particularly the vice-president of the United States, are not particularly convinced by Jack's theory. The idea, however, resonates with Dr. Terry Rapson of the Hedland Climate Research Centre in Scotland. Shortly after Dr. Rapson arrives back in Scotland from the conference, two buoys in the North Atlantic simultaneously show a massive drop in water temperature. Rapson concludes that the melting of the polar ice has begun to disrupt the North Atlantic current and calls Jack to see if his paleoclimatological weather model could be used to predict what, and when it will occur. Jack is surprised because he predicted that the events would not happen in his lifetime, but rather in a hundred or a thousand years in the future. Across the world, violent weather causes mass destruction and chaos.
In Los Angeles, a tornado warning is issued, due to a sudden outbreak of telltale funnel-systems. The first tornado strikes a residential area, where a man saw the tornado touching the ground. Another tornado destroys the Hollywood Sign as seen on a news helicopter. In Downtown Los Angeles, a huge tornado, presumably intended to be an F-5, devastates the entire area. A news van reporting on the storm spots two large tornadoes in Los Angeles International Airport apparently merging as they devastate the plane. As the news crew travels through the city, they narrowly avoid being struck by vehicles thrown through the air by the tornadoes in the Greater Los Angeles. A separate news report shows that the Los Angeles Skyline is destroyed. The on-scene news reporter is killed by a flying billboard, and the Capitol Records Building is shown being torn apart. Eventually, it is shown that the entire city has been leveled.
The US President authorizes the FAA to suspend all air-traffic over the United States. Not long after, three British RAF helicopters that were supposed to carry the Royal Family to safety are flying through one of three massive hurricane-like superstorms when they enter the eye, only to almost immediately encounter a massive and phenomenal temperature drop lower than −150 °F (−101.1 °C) that instantly freezes their fuel lines and their rotors causing them to crash. It is shown that one of the flight crews had opened the door on the damaged craft, only to get instantly frozen.
Meanwhile, Jack's son, Sam, is traveling to New York City for an academic competition, with friends Brian and Laura, arriving there before the airports are shut down. On the flight over, there is severe turbulence, and Sam grabs Laura's hand in fright. The weather becomes increasingly violent with strong winds and torrential rains. After the competition, Sam and his friends are stuck in New York, as the flight they were supposed to leave on was grounded due to suspension of air travel. Sam calls his father, promising Jack that he'll be on the next train home. Sam and his friends, meanwhile, stay with a new friend (that Sam really dislikes) they had met, J.D., and take a tour of New York. The group take shelter in J.D.'s apartment for the night while the storm worsens, forcing tunnels to close due to flooding, which shuts down the Grand Central Station. J.D. offers to give them a ride to Philadelphia, where they can continue to Washington by other means.
As the four walk to J.D.'s car, a Storm surge (or possibly a rogue wave) surges towards Manhattan. The massive wave blankets the island, leaving the streets under several feet of water. Sam and his friends just barely make the shelter of the New York Public Library. In Scotland, Rapson and his coworkers are trapped in their research lab by the deepening snow. They are last seen drinking scotch as their power supply fails. The remainder of the story concerns itself with the proof of Hall's theory and the beginning of a new Ice Age, resulting in millions of deaths. Survivors are forced to flee to the Southern and Southwestern United States and Mexico. Jack decides to make the dangerous journey to Manhattan to find his son. Frank and Jason accompany him. Along the way, Frank falls through the glass roof of a shopping mall, as they are traveling over the top of it which is covered in snow. He cuts the rope he's attached to, sacrificing himself in order to save his friends.
Inside the library, Sam Hall and the other survivors use advice Sam received from his father to outlast the cold. They burn books to keep warm and break the library's vending machines for food. The same night, Sam finds Laura having a fever. He confessed his true feelings to Laura, and they kiss. The following day, after Laura is found to be afflicted with severe blood poisoning, Sam, Brian, and J.D. decide to search for penicillin in a cargo ship that drifted inland during the storm. While within the boat, the three are attacked by a pack of hungry wolves. While the three escape, J.D. suffers a bite wound. During the escape, however, the eye starts to pass over the city with its −150 °F (−101.1 °C) instant freeze, so the three hurry back to the library with the medicine, just barely escaping the freeze.
Jack and Jason soon arrive in New York City, passing the now frozen Statue of Liberty and continue towards Manhattan. Eventually, they find the library buried nearly up to its roof in a snow drift. They manage to find everyone inside the library alive and signal for help, but by then the storms are already dissipating. Jack, Jason, Sam, and all the people inside the library are rescued by a group of helicopters. As they leave, they see people on the rooftops of buildings and helicopters approaching to evacuate them. The movie ends with a satellite view of the Earth, revealing that the entire northern half has been covered in ice. A couple of astronauts in space look down on the earth and report that skies have never looked more clear.