A frozen lake is read as emotion that has gone still and hard — calm on the surface, kept locked away below. Skating across it stands for moving lightly over feelings you are not ready to touch.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.