A search and rescue helicopter has now joined other emergency services in the search for the missing dog walker in Ravenglass.
The missing man is described as in his 70s, 5ft 8”, of slim build and is bald. He was wearing a green fleece, green suede trousers and walking boots.
He was last seen entering the water at Ravenglass Estuary at around 9am this morning.
Anyone who may have seen someone matching this description is asked to call Cumbria Police on 101 and ask for the duty sergeant at Whitehaven Police Station.