Patterned Lake

The lake surface almost looks like white clouds scudding across the sky (but wait, why do clouds 'scud'? I think glide or float describes their fluidity better. Scud makes me think of stop-go action that is not smooth or fluid ... but I digress)

The lake surface is only flimsily iced over, and has an amazingly different pattern from usual, on its surface.

It could be an artist's splashes of white paint on a blue canvas ...

There are no clouds in the sky, so these white patches are not reflected clouds.