Think of it more like a very long period wave, much like a tide, but on a much shorter time period than the tide. Tides, waves (periods on the order of seconds)

Think of it more like a very long period wave, much like a tide, but on a much shorter time period than the tide. Tides, waves (periods on the order of seconds), and tidal waves (or tsunamis) are all fluctuations in sea level. Water can be moved when the waves encounter enclosed bays or harbors. Think of the water level dropping 3 ft over 20 minutes in front of a harbor entrance and imagine the currents that can result. Here's an example of observations from coastal California (red line shows sea level measured every 6 minutes: https://tidesandcurrents.noaa.gov/waterlevels.html?id=9412110&bdate=20220114&edate=20220115&units=standard&timezone=LST/LDT&interval=6 https://tidesandcurrents.noaa.gov/waterlevels.html?id=941211... It is truly amazing - I'm not surprised that it's hard to believe.