Approximately 7,600 PG&E customers lost power Tuesday morning just before 11 a.m., and the company says the cause was a metallic (mylar) balloon coming into contact with utility equipment.
Power was out primarily "in the area of Columbus and Greenwich streets," per the Chronicle, but as you can see on the outage map from PG&E below, clusters of customers in the Pulk Gulch vicinity and others south of the Broadway Tunnel also appear affected. (The green pinpoints indicate outages of up to 49 customers.)
PG&E says most customers' power was restored by 11:52, and a company spokesperson would like to "remind our customers of the dangers of metallic balloons, which have a silvery coating that conducts electricity." When the balloons strike PG&E lines, "they can short transformers, melt electric wires and cause power outages, all of which pose public safety risks."
Mylar balloons should never be released into the air — they also are not biodegradable — and PG&E recommends that anyone carrying a metallic balloon attach a weight to its string to prevent accidental flyaways.
They also recommend never bundling these balloons together, and keeping them indoors whenever possible.
"In the first four months of 2020, metallic balloons striking electric lines caused 94 power outages in PG&E’s service area, disrupting electric service to more than 44,000 homes and businesses," the spokesperson says.
The last couple of unplanned outages in the city occurred in May in the Lower Haight, Cole Valley, Alamo Square, and Hayes Valley areas.