Through out history theologians and pastors have tried to answer such questions. Evil and suffering are very hard to synthesize with belief in a loving God. I don’t pretend to have the answers, but let me share some key thoughts.
First, God is a loving, powerful God but not just a loving, powerful God. He is also wise, all-knowing, holy, righteous, just and wrathful. Any adequate answer about suffering must deal with all of God’s attributes, not just one. For example, while preventing all suffering from happening might seem loving, it might also violate other aspects of God’s character.
Second, because God is all-knowing, He sees not just the immediate suffering, but how that suffering connects to every other event—past and future. Jonathan Edwards’ perspective is quite helpful in this regard. He suggests that God sees through a microscope and a macroscope. In the microscope God sees each event individually. In this regard He rightly hates suffering. In the macroscope God sees each event as it connects to all other events. In this way, He may be inclined to allow that which He hates, because of outcomes we can never fathom.
Ultimately our response to tragedies like Haiti’s comes down to trust. Can we trust God enough to say, “While I may never understand, I trust God’s reasoning in allowing this tragedy.” Having trusted His reasoning, we are then free to respond with His love.