The Lincolnshire Wildlife Trust has repeated earlier pleas to the public to stay away from the Gibraltar Point Nature Reserve following the severe tidal surge last week.
Staff said coastal flooding at the site was unlike anything they’d ever seen at the site, and that a large lake at least a metre deep was created when seawater flooded the freshwater marsh.
Many paths are damaged and some remain underwater, sparking fears for the public’s safety if they attempt to traverse them.
“The saltmarsh and main car park at Gibraltar Point do occasionally flood on the highest of tides but staff had never seen anything like the floods caused by the tidal surge,” said the Trust.
“The tide overtopped ‘The Hump’ (the flood defence at the entrance to the car park) and breached sea defences in at least five places.
“Seawater flooded into the Freshwater Marsh creating a large lake at least a metre deep.
Many paths are damaged and some remain underwater.
“The Visitor Centre and Wash Study Centre inundated with water to two feet deep and with such force that furniture was moved,” they added.