I did a search today in yahoo and google on "katrina". It was interesting to examine the results. I found Yahoo and MSN results were more relevant to hurricane katrina and initially there was no results in Google relevant to the hurrican "katrina". Few hours hours later some results poped up. But its already 3rd day (if not more) for the "katrina hurrican" story.
I think if search engines try to optimize, carwl and present relevant results for top keywords it would be highly helpful. Kudoos for MSN and Yahoo in this aspect!