Four-alarm fire in San Francisco

I was writing email last night and happened to look out the window. There was a huge fire in the Bayview. While I was watching, blue fireballs exploded. It was unnerving, to say the least. The San Francisco Fire Department upgraded it to a four-alarm fire and finally contained it around midnight. Twitter was the best source of news while it happened (the Chronicle has a story about it today). The SFPD media account and the fire fighters union posted running updates. The building was totally destroyed, but there were no injuries.