Just in the last few days, I've been drawn to YT videos with interviews of Robert Schwartz, a hypnotist, concerning soul contracts, which are plans we make pre-birth, for the lessons we wish to learn in the next incarnation. He's written two books about the subject.
I cannot post links yet, but in his blog he gives his perspective on your question, including a (possible) meaning behind mass disasters. His website is called your souls plan dot com, click on his blog, the entry is dated 28 Nov and titled "What is the purpose of catastrophic events?"
His answer is, "yes, we do - they are in our soul contract" and he then expands on it. Take it or leave it; it sounds brutal to suggest that victims of natural disasters or war/terror and the like, actually chose this, yet I find his take on it convincing. I find the whole concept of soul contracts very convincing.
(Probably because I am currently being hit on the head with it and ugh, the headache is mean. I have this picture of my HS and Guide taking deep, patient breaths and saying "okaaayyyy, let's try this again another way, from the top...."
I'm going to get it right, this time - firm intention is set!)