Tidal waves

In last nights dream we were swimming in the ocean, enjoying the swell at the time, riding the waves in etc. Before very long at all each wave was noticeably getting larger and stronger as was the noticeably abnormal draw back before the large wave. Wave after wave we began to realise something was not right and the waves were now beginning to thrash the shore line above normal high tide marks. So high and frightning were the waves now. Swimmers no longer able to raise above them, getting pulled under. On looking from the shore we realised we had to run. Each wave reaching new heights raising the water levels, washing down coastal buildings etc. It was time to get to higher ground as fast as we could.