A reportedly "small" fire in an underground PG&E vault near the intersection of Laguna and Hayes streets Wednesday night caused a power outage for 9,000 utility customers — including the San Francisco Ballet, performing at the War Memorial Opera House.

PG&E spokesperson Karly Hernandez tells the Chronicle that the outage began at 7:52 p.m. and was the result of an "equipment failure." The affected customers extended from the Lower Haight to Civic Center, and the outage happened in the middle of a ballet performance that is part of the SF Ballet's current selection of contemporary ballet called "Classical (Re)vision," and the performance had to be canceled.

Customers reportedly stayed inside a candlelit Suppenküche drinking beer, per the Chronicle, though restaurants in Hayes Valley mostly had to stop serving during peak dinner hours.

But the "small" underground fire looked kind of serious when one Twitterer captured both smoke rising from the sidewalk at Hayes and Laguna, and a small explosion that would have most certainly injured someone had they been standing near it. (The area was taped off with caution tape before the explosion occurred.)

PG&E was able to restore power to all affected customers in about two hours, according to Hernandez, by 9:43 p.m.

The total affected area, according to PG&E's website, looked like this: