Spits are narrow, elongated landforms that extend from the shoreline out into the water. They are formed by the action of waves, specifically longshore drift and wave deposition. Longshore drift is the movement of sand and other sediment along the shoreline caused by the angle of wave approach, while wave deposition is the process by which sediment is dropped off and deposited by waves as they slow down and lose energy.
As waves approach the shoreline at an angle, they cause sediment to move along the shore. When the shoreline takes a bend, the waves slow down and deposit the sediment they are carrying, forming a spit. The direction of the spit is determined by the dominant direction of the waves and longshore drift.
Over time, spits can grow longer and wider as more sediment is deposited by waves. Spits often have a curved or hooked shape at the end, which is caused by the change in direction of the waves as they reach the end of the spit.