And when the barbarians saw the [venomous] beast hang on his hand, they said among themselves, No doubt this man is a murderer, whom, though he hath escaped the sea, yet vengeance suffereth not to live.
Note 4 at Ac 28:4: It is true that God has pronounced judgment against the ungodly, and this judgment has at times been carried out by beasts (Nu 21:6, 1Ki 13:24, and 2Ki 17:25) as well as natural disasters such as storms (Jon 1:4). However, it is not true that all adversities such as these are a sign of judgment. The storm that Paul was caught in was not God's judgment on him, and this snake biting Paul was not God's punishment either.
Tragedy can come from three sources: God, Satan, and violation of natural law. As mentioned, God has used nature to bring judgment. However, the New Testament believer is exempt from this punitive judgment of God, since Jesus bore that for us (see note 8 at Joh 5:14 and note 2 at Joh 9:2).
Satan is the source of much of the calamity that people ascribe to God (Joh 10:10, Ro 6:16, and 1Pe 5:8), and many problems happen because people violate the natural laws that God put in motion. If people drive recklessly and kill themselves, it's not God or the devil that killed them. They violated natural law and paid the price.
It is incorrect to believe that God controls everything and, therefore, always has some redemptive design in our tragedy. That type of thinking will lead us to ignore the devil, thereby giving him a free hand to destroy our lives. And it will also cause us not to use wisdom concerning the natural laws, thinking that nothing can happen unless God wills it.