Crews are working to determine what caused a large sinkhole at a major Union City intersection Wednesday afternoon, city officials said.
Police reported the roughly 12- by 10-foot sinkhole at the intersection of Alvarado Boulevard and New Haven Street just before 2 p.m.
Alvarado is closed between Fair Ranch Road and New Haven Street.
Trucks are still able to leave from the fire station at that intersection, though they can only turn right on to Alvarado, Alameda County fire spokeswoman Aisha Knowles said.
The hole was first reported by a passerby, who knocked on the firehouse door and alerted the firefighters to the sagging roadway. The firefighters went outside, saw what was happening, and called the police, Knowles said.
It is unclear what caused the sinkhole and the roadway remains closed. Traffic disruptions complicated matters for parents picking up students at nearby Alvarado Middle School, school officials said.