Looks to be on the block north of St. Luke’s. I called a friend that lives on that block:
Me: You’re not on fire are you?
Her: No, I’m okay. Thanks for asking. Everybody keeps calling me to ask. [...] I heard someone shouting that it was her house.
So, apparently it was someone’s house.
Update: Wow, FriendFeed debuted search just in time! I searched “mission fire” and came up with something great via Scott Beale (the same dude that hipped me to the fact that FriendFeed now has search): twitterer ceedub is right under the inferno:
Link to cee-dub on Flickr.
