There has always been natural disasters and suffering. These are not the first major hurricanes, that was not the first tsunami, and 9/11 was not the first terrorist act in the world. Some of these things are just hitting a little closer to home. I think as history passes, disasters seem to be "worse" to us for a number of reasons. Media saturation has grown (for example, there are 20 news channels you can watch this stuff on 24 hours a day whereas 40 years ago you just had a few networks.) The internet gives us access to discuss these things and read articles about them with the click of a mouse. As cities become larger, population more dense, and properties more valuable, etc, there is more to lose.
I don't necessarily believe this stuff indicates the end of the world. Yes, there will be signs, but I think they will be very out of the ordinary things. As tough as it is to think about, hurricanes are ordinary things, but the intensity and frequency of them tends to be cyclical, and many of us were not living during the last cycle, and if we were, we were not aware as much of the devestation due to the fact we did not have the same technology we do today.
And to answer the questions on whether there will be signs or if no one will know when the end of the world is, based on my Christian faith I believe it is both. I believe there will be signs to tell us it is near. But I don't believe we will be able to pinpoint to a day, a month, or even a year. I don't expect anyone that does not have the same religious beliefs I do to agree with me however, this is just my opinion.