10:15 AM: Authorities have closed a lane of Larkin Street near San Francisco’s Civic Center for the rest of the day after a large amount of steam began billowing up from an underground vault this morning, a San Francisco Public Utilities Commission spokesman said.
Crews responded to the intersection of Larkin and McAllister streets overnight after rainwater began to pool in an underground vault directly over a steam pipe, which evaporated the water and caused steam to come up into the intersection, SFPUC spokesman Tyrone Jue said.
A few months ago, an emergency water pipe for the San Francisco Fire Department broke, damaging a storm drain at the intersection, Jue said.
Since then, steam has often been seen coming up in the intersection because “anytime any water pools up or passes by that steam pipe, it heats up and evaporates,” he said.
Crews are working this morning to suck the water out of the vault, and will look to see if there was any damage to the pipe, Jue said.
One southbound lane of Larkin Street will be closed between McAllister and Fulton streets until at least the end of today, Jue said.
The SFPUC is also working on a long-term fix to prevent similar problems from occurring at the intersection in the future, and the street may be closed longer depending on the extent of damage found inside the vault, he said.
6:56 AM: An underground utility pipe appears to have ruptured in San Francisco this morning, disrupting traffic around City Hall.
The San Francisco Fire Department responded to reports of a broken steam pipe at Larkin and McAllister streets in the Civic Center at around 6 a.m., Lt. Mindy Talmadge said.
Firefighters determined that the broken pipe emitting steam onto city streets does not pose a danger to the public, Talmadge said, and that the Department of Public Works will respond to repair the rupture.