Crescent City sits at the top of the California coast, where the continental shelf is narrow and North Pacific swell arrives with little to slow it down. The harbor has a documented history with tsunami surge for the same reason: the bathymetry that focuses swell focuses everything else too.
Buoy 46027 reports no water temperature. That is not a fault in this site — the instrument is simply not on that platform, which is why the water temperature figure above reads as absent rather than as zero.