Power Outages In San Francisco Bring Down Major Websites

6 back-to-back power outages hit the SOMA neighborhood of San Francisco Tuesday afternoon causing major havoc with popular web services. 365 Main is down, along with craigslist, Technorati, Yelp, AdBrite and SixApart (including TypePad, LiveJournal and Vox). It caused some problems with servers used by Current TV and Second Life.
Pacific Gas and Electric (PG&E) is currently working on the issue. It is now estimated that over PG&E 30,000 customers are with out power.

So the big question, where is the backup power at the data centers used by these services? UPS and diesel generators should normally help situation like this.