From The Tribune Review:
"The falls began icing over as soon as the temperature dropped on Sunday night, a phenomenon Waggoner said had only happened two or three times in her 30 years of work with Fallingwater.
As temperatures are expected to reach a balmy 50 degrees this weekend, the waterfall that captivated Wright will likely thaw.
“The ledge that creates the waterfall is a cantilever,” Waggoner said. “He saw that ledge and then created a series of cantilevers that reconnect the house to the site, so that was clearly the inspiration for the house.”"Staff are watching the structure carefully for cracks or any signs of damage.