Walking On Water: Physics of Clear Ice

A video went viral yesterday showing two hikers in Slovakia walking across a frozen lake. What is amazing about this lake is the fact that it froze crystal clear such that the hikers appear to be walking on calm water.In cased you missed it, here is the video: Now, like any self-respecting scientist, I tried to get APS approval to repeat their hike, you know, just to verify the experimental results, but sadly no can do. The stark and beautiful scenery of the Slovakian mountains will have to wait...