If you say "Everything happens for a reason," be careful you do no commit idolatry. If you say "God is in control," again, be careful. Sure, you will tell me of Biblical prophecies and stories where "God's plan" was explicated and executed. But that is the Bible. And I urge you to be careful that you do not commit idolatry when reading it.
If you say, "Japan suffered its devastation for a reason," then I would say, "An explanation of that devastation is the abrupt shift of the tectonic plates along that side of the Pacific Rim." If you say, "No, there was a greater reason, a theological reason" then you, yourself, stand on shaky ground.
Will you be so bold to say that this "reason," this "rationale" was so that God's glory may be made manifest? Perhaps, you will show me such textual "proof" in John 9, where Jesus heals a man who was born blind so that the works of God may be displayed in him? Will you be so bold to say, "Yes, I believe that thousands of people died and an entire nation was crippled so that the works of my god may be displayed"? Because that's a pretty bold claim. Is this your "reason" for why things happen? Is this your rationale? Are all events (natural or otherwise) to you so supernatural?
We saw similar circumstances with Katrina, but this is on a completely different scale. And yet the questions still remain. A lot of effort, over the millennia, has gone into why things happen – and who/what is to blame/praise. And from this effort, we have developed various kinds of cause, among them those assigned neutral, evil, and good. And with cause/effect, we have ethics.
Shall we include ethics with our natural disasters? To what shall we assign Japan's utter tragedy? Will we be hubristic and idolatrous to do so? Shall we ascribe architectonic meaning to this and "I know why! I have a reason for all of this!" – even if that reason is "God has God's own reasons"? Because if you do, what kind of god do you believe in and ascribe action and event? If it is a god who actively allows such things to happen to demonstrate how awesome that god is, then, to me, that is of the most cruel kinds of gods. Will you be so bold to say, "we live in a world so fallen because a single man and woman in their disobedience brought forth such natural cataclysm upon thousands"? Will you be so bold to say that sin caused this tsunami?
Better that we say "I have no reason why this happened. Let us help one another in these terrible hours," than claim, "I have a reason for all of this: everything happens for a reason." Because your reason seems quite unreasonable.