The effect of wind stress on sea level and hence on tidal heights and times is very variable and depends largely on the topography of the area. In general, sea levels are raised in the direction of the wind, often called wind setup. A strong wind blowing onshore will pile up the water and cause high waters to be higher than predicted, while winds blowing off the land will have the reverse effect. In addition, winds blowing along a coast tend to set up long waves which travel along the coast, raising the sea level at the crest and lowering it in the trough.