Are cataclysmic events connected with the end of the tribulation and Christ's return?
Yes. The context explicitly states that cataclysmic events are associated with the end of the tribulation and the return of Christ. This is contrasted with the rapture, which is described as a silent removal of the believer, with no cataclysmic events and no great upheaval.
Les teaches that these cataclysmic events are associated with the end of the tribulation and the return of Christ, and he urges his audience to keep them in mind. He plans to show from Scripture the graphic difference between the silent removal of the believer at the rapture—when there are no cataclysmic events and no great upheaval—and these tribulation events, proving they are not one and the same. He also observes that many people are unfamiliar with the rapture or the idea of the second coming in two parts.