I didn't think the recent shootings at Virginia Tech were going to hit me at all until I heard on the news (while grabbing dinner at Sreees) that a prof who was a holocaust survivor died while trying to bar the door to his classroom (to save his students) with his body. When he was in the camps, I imagine he would've laughed to think that so many years later he would die in such a way.
In the larger scope of tragic events, thirty people is nothing. I recall being stunned by the Indian Ocean earthquake in 2004 as the death toll steadily climbed, and hearing about the continuing stream of deaths in events more like this during various cultural struggles does a good job at keeping me from feeling cheery very often.. but having something happen quite this near does make it easier to feel it. As it's said, "one death is a tragedy, a million deaths a statistic". That doesn't necessarily make it easier when something does manage to make an emotional impact (and I don't want to belittle it).