Roger Olson and John Piper, round two. Qualifications from Olson follow.
"True, in this particular blog entry Piper does not explicitly say the tornadoes were God’s judgment on those towns. He does say, however, that the tornadoes were “God’s fingers.” In light of everything else he has written and said about calamaties and catastrophes, it is clear to me that he believes not only this tornado outbreak but every natural and man-made disaster (including the 9/11 terrorist attacks on New York and Washington, D.C.) are from God and not only in some attenuated sense in which most Christians would say they are from God by concurrence. (That is, by God’s permission and granted ability as the creator and governor of nature.)"Olson/Piper II
Olson very often engages with folks who comment. If you have something to contribute, I'm fairly certain he'll answer. I might even post something myself. ;-)