You worded your questions just fine. After Katrina, my New Orleans astrologers group had a ball doing charts for the storm, for New Orleans, and for the Gulf Coast. We were looking at the monster named Katrina from all angles. One of our astrologers even wrote published articles about the storm and our discoveries. I think she had a two-part article in one of the magazines or newspapers devoted to astrology. I know she had something published in The Mountain Astrologer at the time, possibly Feb/Mar 2006. Somewhere around there.
Anyway, part of our discovery was if we used the time the French first set eyes on the area which would become New Orleans, 3 March 1699, it gave us additional insight than did just using either of two charts normally used for the city, which I can't remember the two dates just now.
You can see "possible" disaster in the near future (using a certain time frame) and the city of the locality, or you can wait until the storm brews to see how bad it will be and if it will come calling. Being from the Coast, you know waiting to see what happens is the first key to major calamity. So, naturally, using the area's chart with the storm's chart is crucial before disaster strikes. Using the area's natal chart, with current progressions and transits, etc., is a good way to see if the unmentionable could be looming.
Of course, using just the charts of the city, the astrologer who wrote the articles told us she feared for certain dates in 2006. We had no problems then, but we did have a bit of havoc in 2008, so I guess even good astrologers can misread something if personally involved and extremely shell-shocked from a recent event.
