Are you also hearing helicopters and sirens in the Mission? Per KRON 4 (and the Chron), there's a four alarm fire at Valencia and 25th, which is in a residential building. The reporter on the scene saw some people coming out on stretchers and from the ambulances we're hearing, it sounds like people are going to the hospital. We'll do some more research on this online and report back with links and pictures when we find any. Leaning out our window, we can report that the smoke coming from the building looks bad.
Update: Chron says the fire is near the Dovre Club, which is filled with folks celebrating St. Patrick's Day.
Still looking for pictures, but it looks like there was a fire on that same block a few weeks ago.
Found a picture, at ABC 7. Video footage from CBS 5 is here. It looks like the smoke is dying down, from our window at least.
A much better picture of the fire than the one we swiped off ABC 7, by reader Chris R, off flickr. Thanks, Chris!