ha, "largest swell in decades?" I don't know WHAT they're talking about. The only reason some reporter is making some big to-do about this little bump, is that it's about the famous annual surfing competition. Truth be told, this is not a "big swell". Oh sure, maybe for surfer purposes, granted, suitable for surfing, etc.. But for beach erosion (our purposes) , no.
The buoy reports right now are a measily 10-ish ft. in Monterey bay. Ho hum. There's a long period interval though, which perhaps is great for surfing (so that the "lines" are "clean", as opposed to rapid intervals, which are "sloppy" for surfing).
But as it pertains to md'ing and erosion? Nah. A buddy of mine just checked out Santa Cruz main beach, and it's lame as h*ck. Sterile. No erosion.
Wake me up when the swells hit 15 ft. or better. Or if coming from the W or SW, sure, maybe as little at 5 to 10 ft. Otherwise, that article is making a big to do about nothing.