The Erskine Bridge remains closed to traffic on one side amid fears someone has plunged into the water.
The busy stretch was closed in both directions shortly after an emergency call to police at 11am this morning.
Police and the coastguard are in attendance at the scene.
The northbound carriageway reopened after an hour but the southbound carriageway from Dumbarton to Renfrewshire remained closed.
Huge traffic delays have been reported in both directions. Drivers have been advised to use alternative routes.
More to follow.
