The swim was cancelled because of cold water and debris. First thought I had was "how bad can it be, let us do it".  But they were right. The Auburn Journal later reported, "Lake Clementine was declared off limits late last week after half a week's worth of rain raised the lake's water line to levels not seen for nearly a decade...choked with everything from tiny sticks to Cadillac-sized logs.  The debris field was so thick Thursday and Friday, Struckman said that it looked as if you could walk across it.  The runoff from Sierra snow melt dropped temperatures in the lake to a frigid 49 degrees Thursday night, Struckman said."