The northbound SR 99 First Avenue Bridge in Seattle got stuck in the open position on Wednesday, causing long backups during the morning commute.
Traffic is being diverted off South Holden Street, according to the Washington State Patrol.
Washington State Department of Transportation maintenance crews were on-site, troubleshooting at around 6:30 a.m.
By 7:30 a.m., the bridge was still stuck, with residual traffic backups of nearly three miles on SR 509.
By 8 a.m., WSDOT reported seeing backups of more than a mile on SR 99 and 3-plus miles on SR 509.
Troopers and WSDOT crews are working to clear vehicles that are stuck in the backup.
There is no estimate on when the bridge will reopen to traffic.
Drivers were told to expect delays or plan alternate routes.