A sandbar is a hidden obstacle just under the surface, read as an unexpected snag that can stall progress. Folk tradition also sees it as a temporary resting place appearing at low tide.
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.