Work has started to lift an articulated lorry from the Montgomery Canal along the A483 road near Abermule.
The lorry, carrying animal feed, crashed into the freezing canal water on Monday afternoon.
The driver escaped injury and yesterday feed being carried on the lorry was transferred to another vehicle.
Today the road was closed at 9.30am to allow a specialist crane to be brought in to lift the vehicle out of the water.
A diversion has been put in place for motorists, taking them from Newtown to Churchstoke and then on the A490 to Sarnybryncaled at Welshpool and vice versa from Welshpool.
However, many motorists are expected to use minor and B roads around the area which is likely to cause congestion in surrounding communities.
Today, Powys County Council said it was too early to speculate on what damage has been caused to the road.
Initial inspection suggests little damage except to the crash barrier and verge.
"An early inspection hasn't shown any damage to the road itself, but damage has been caused to the crash barrier and the roadside verge which will need to be repaired," said a council spokesman.
"A thorough inspection will take place once the lorry has been removed from the canal, which will identify what work is required.
"It is too early to say when the works will start and how long they will take."
It is not known what damage, if any, has ben caused to the historic Montgomery Canal.
Natural Resources Wales has put emergency plans into place to prevent any contamination from the vehicle escaping along the canal.
Booms and soak mats have been placed in the canal.
It is not known if the lorry has caused damage to fabric of the canal and whether this will need work or part of the canal to be drained.
The road is expected to open this afternoon, although officials said it could take over five hours to safely remove the vehicle