Nature Plays in the Cold

I walked up to the lake in the hills thinking It would be hard-frozen by now, but it wasn’t. The ice looked so thin I didn’t even test it. But what I found instead were these wonderful ice-crystals, all along the edge of the lake. I know it is really unusual to see crystals this big, and I know they form like this when the water is just at freezing point and the temperature is just below 0° C and it freezes relatively slowly. But beyond that my knowledge stops.
Nature’s own Christmas art!!