Sidewalk Work May Have Weakened Trees That Toppled and Knocked Out BART Power

San Francisco Public Works officials and PG&E are investigating whether recent sidewalk repair work in the city's Mission District weakened the roots of several ficus trees that fell Friday morning, causing a power outage that shut down the 16th and Mission BART Station for hours.

The seven trees toppled over on the south side of 16th Street — where Harrison Street and Treat Avenue come together — sometime after 3 a.m., pulling down power lines and poles. That knocked out power to 2,550 customers, PG&E spokeswoman Andrea Menniti said.

Most of those customers had their power restored within 45 minutes, Menniti said, but electricity was not restored to the BART station until around 7:15 a.m.

The trees fell during a storm that brought gusty winds and brief, heavy downpours to parts of the city overnight.

The sidewalk repair work was done within the past month, according to San Francisco Public Works spokeswoman Rachel Gordon.

"Ficus trees are more vulnerable to failure," Gordon said. "One factor was the storm that was going through. With the water and high winds, that does make trees that are vulnerable a little more vulnerable."

City arborists began working to remove the damaged, fallen trees Friday morning, Gordon said.

No one was injured and the agency is not aware of any damage caused to private property, she said.

The California Public Utilities Commission is looking into the outage.

"We have reached out to PG&E for information on the event," said CPUC spokeswoman Terrie Prosper.

BART spokeswoman Alicia Trost said that the 16th Street Station was not yet open for service when the outage occurred.

Trains did not stop at the station during the outage, and BART brought in two generators: one to power the station's fare gates and lights, the other to power escalators and elevators. Agency crews were still connecting the generators when PG&E restored power.