I love all of the good guesses and I must say they were all very good!
Photowannabe however came extremely close. Sue was the only contestant to see the ice!
The Meadow Grounds Lake is in the process of freezing over. A few yards from shore I noticed this hole in the thin ice. I assume it was caused by a spring in the lake bed creating an upwelling of warmer water. As the waves rolled across the open water and ran up against the ice sheet they caused water to well up through this hole and then recede as the wave passed by.
So as you now see, it was totally natural, soon the lake will be completely frozen and the ice was too thin for me to approach closely.
Today’s photograph is of the same ice hole with the wave receding.
Thanks everyone for your comments. I must admit; if I had found this photo on one of your blogs I would have been totally stumped :)