It is not known when inspection works will be carried out on the closed bridges across West Cumbria.
The bridges, which were shut on Wednesday when heavy downpours caused rivers to flood, need dive inspections carried out.
But the county council say this cannot be done until water levels and speeds drop and have been unable to provide a date.
This will come as a blow to thousands of motorists who use the routes, especially those heading to and from the Sellafield site, who face huge tailbacks.
A council spokesman said: "Dive inspections may be required to check whether bridge foundations are damaged.
"This can only happen when water levels/speeds drop.
"We cannot open a bridge without assessment, 2015 floods show clearly that fundamental damage can be out of sight below water line.
"We will get inspections done ASAP and will work to improve diversion signage and management."
Traffic was brought to a standstill along the A595 this morning as drivers attempted to get to Sellafield.
And there are reports it took more than two hours for workers to get home last night.
The closed bridges are:
Holmrook Bridge (A595)
Kersey Bridge (between St Bees and Beckermet)
Egremont Bridge
Forge Bridge (near Eskdale)
Smith Bridge (near Middleton)
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