Tests are being done on 1,800 bridges in Cumbria in the north-west of England to see if they will collapse in the floods.
Lots of them were damaged after heavy rain caused an increase in the amount water running underneath them.
Six have already fallen down, and another six are shut, because they are too dangerous to cross.
More than 1,300 homes were swamped in floods, and people have been told not to return as more rain is expected.
On Friday a policeman died when a bridge he was on collapsed. He had been directing traffic to safety at the time.
Elsewhere, in Devon a canoeist died and in Wales the search is on to find a woman who was swept away along the river Usk.
There are currently 18 flood warnings in force across northern parts of England, Scotland and Wales.