Well...
Besides being personally effected here in NYC.
I lost sales in my finance niches being that the markets are closed.
I lost some sales with client meetings I was suppose to have yesterday, and being there is no subway still probably won't happen till the end of the week.
I lost about 18% of my normal sales volume, probably due to the HUGE power outages across the North East.
It won't last long though...
The worst disaster ever to effect my business was a tsunami in the Philippines when I had 15 workers in an office over there and it was completely wiped out. That took weeks to recover.