(Photo courtesy of Jim McAnulty)
Update: 8:40 a.m.
Debris has been cleared and the road has reopened.
City street department workers used a front loader to clear dirt and rock from road.
Billings police Lt. Neil Lawrence said Thursday morning in an email that Zimmerman Trail has been closed due to rocks falling on the roadway.
Lawrence did not provide any further information.
This is a developing story. Check back for updates.