Here's the scene at Haight and Fillmore just a few moments ago around 4:30 p.m. this afternoon. A KCBS crew on the scene reports it's a 3-alarm blaze.
This afternoon's fire is the second 3-alarm residential blaze in the Lower Haight in the past three months. Back in July, a similar fire destroyed a home less than two blocks away on Waller Street.
Update: Emergency_in_SF reports the fire was upgraded to a 4th alarm (unconfirmed) (confirmed) and over 150 of SFFD's finest were on the scene.
A few news helicopters were spotted over Alamo Square and the Lower Haight. ABC7 is streaming live from the air. At about 5 p.m. the blaze looks to be mostly under control, with firefighters on the roof dousing the remains of the flames.
Update II: If you're heading home on Muni on any of the lines that run along Haight Street or Fillmore (6, 22 and 71) note that those lines are being rerouted.