In Puget Sound, there are areas where gray whales feed on buried prey in tidal zones specifically the beach at Langley) where they basically wind up liquefying

In Puget Sound, there are areas where gray whales feed on buried prey in tidal zones specifically the beach at Langley) where they basically wind up liquefying the sand, sucking out the food, and letting it all settle back down. Then, when the tide is out, there are these slightly depressed poorly consolidated areas that are effectively quicksand -- you can go from hard sand to knee deep in a few feet/seconds.