Crossing Tahoe: A Swimmer's Dream. On a frosty morning in September 2007, Karen Gaffney plunged into the dark waters of Lake Tahoe. Her ambitious goal: to join the few ultra-swimmers who’ve crossed the width of the lake and to be the first woman to cross in the bone-chilling cold of late September. Having Down syndrome was the least of her challenges. To conquer the nine-mile distance, she would need all the strength, courage and spirit she had.