I know it's comparing freshwater to seawater, but this pic is of Derwentwater in Jan 2010:
There was ice covering most of Bosham Creek in Chichester Harbour in 2001 (or was it 2000?) but scarcely thick enough for a duck to walk on.
Slightly off-topic but told to me by a colleague when I worked in Manchester: his father lived in Keswick and in the 1930s Derwentwater had been frozen for several weeks, so his father went out for a regular evening skate after supper. As the freeze went on, the level of the water had dropped and there was a gap between the water and the ice sheet on top, with the sheet being supported by pillars of ice. That evening his father went out as usual, with s southerly wind getting up, and there was suddenly a cracking and groaning sound. He got off the ice quickly, and fortunately so - the wind ha got into the space under the ice and within half an hour the ice covering the whole lake had broken up into smallish floating patches of ice, not big enough to support a man.
War does not determine who is right, only who is left - Bertrand Russell
Chichester 12m asl