10:42 AM: SDOT has just acknowledged the “mechanical issues” that have kept the West Seattle low bridge closed to surface traffic for more than half an hour. Above is the latest webcam image. Updates to come.

10:56 AM: Metro has officially rerouted buses, according to alerts just sent. As for the low bridge, after a tip (thank you!) we watched the webcam for a few moments, and the problem appeared to prevent the bridge leaves from completely rejoining – they swung partly open and tried to close a second time, and then came SDOT’s confirmation. A similar problem happened July 9th and kept the low bridge out of service for more than two hours; that problem was eventually deemed “electrical.” That’s also what was blamed for an hourlong closure in May.

11:01 AM: And the low bridge has just reopened.

2:21 PM: We asked SDOT if these “issues” were related to the ones that caused the May and July closures. Spokesperson Mariam Ali says no: “Today’s issue is different from the problems in July and May. Today, crews were doing preventative maintenance work around the far side pier. During the cleanup work, a rusted coupler (a device for engaging and disengaging the interlocking connection between the shore and a movable bridge span) for one of the conduits containing wires to one of the sensors separated and damaged the wire. The damaged wire was unknown until the bridge had cycled through an opening request and was going back to a closed position. At that time, an alarm had sounded noting that the computer was not receiving a signal, due to the damaged wire, from the sensor. The electricians were able to pinpoint the issue quickly and replace the broken wire.”