Barents Sea, August 12th, 2000. During a Russian naval exercise, and after suffering a serious accident, the K-141 Kursk submarine sinks with 118 crew members on board. While the few sailors who are still alive barely manage to survive, their families push for accurate information and a British officer struggles to obtain from the Russian government a permit to attempt a rescue before it is late. But general incompetence are against all their efforts.

As a new day begins in the town of Silverton, its residents have little reason to believe it will be anything other than ordinary. Mother Nature, however has other plans. In the span of just a few hours, an unprecedented onslaught of powerful tornadoes ravages Silverton. Storm trackers predict that the worst is still to come, as terrified residents seek shelter, and professional storm-chasers run toward the danger, hoping to study the phenomenon close up and get a once-in-a-lifetime shot.

An earthquake shatters a peaceful Los Angeles morning and opens a fissure deep into the earth, causing lava to start bubbling up. As a volcano begins forming in the La Brea Tar Pits, the director of the city's emergency management service, working with a geologist, must then use every resource in the city to try and stop the volcano from consuming LA.