UPDATE: Streets are now open.
A gas leak at 24th and Bryant, smack dab the ninth circle of San Francisco's gentrification techster hell, has prompted a temporary street closure this afternoon. According to Mission Mission, it is the reason why some Missionites are hearing helicopter overhead.
Firefighters have evacuated nearby homes and businesses. People meandering in the area have been advised to scram. The leak has yet to be capped. Ellen Huet (of SF Chronicle) tweets that the "[s]mell is pretty strong."
We'll update as soon as we know more.