Tea Leoni dies when the first comet hits. The crew of the shuttle dies blowing up the second comet and saving earth. Leo finds Sarah again, and runs off away from the tidal wave with her baby brother. Her parents die.
Trivia: If you happen to have the DVD version of the film, have a look at one of the trailers. In the movie trailer they show the comet hitting the ocean at an almost right-angle. In the actual movie the comet enters the atmosphere at an angle, thus letting the people watch the comet travel to across the sky into the ocean.