I assumed it was open to the Pacific Ocean, and even on normal days, waves would roll in, smash against the seawall, sending spray in the air. If the water was at all rough, huge amounts of seawater would go up over the sidewalk in a massive deluge, and even hit the road. When it was REALLY rough, the water would go all the way over the road and get the eight story (I think) apartment building on the other side of the road wet.
This was in the sixties, but I was able to see the area on Google Earth. Heh, funny. I always thought it was open to the Pacific, but looking at Google Earth, I can see it wasn't. But the body of water was large enough for the prevailing winds to kick up waves...:) The arrows showed where the waves came from and where we ran...:)
Heh, we would play chicken with the waves. Me and a friend would get at a point where the waves began hitting, and run full speed without stopping. As we ran with all our might, we would both laugh hysterically while our faces were turned to look at the incoming waves. The rule was, you couldn't slow down or stop. Once you began, you had to run all the way to the end at full speed.
We would get hit so hard sometimes we would get knocked off of our feet, and needless to say, one wave was enough to drench you through and through, all the way, completely. If you got to the end, huffing and puffing, hands on knees, we would look at each other, then immediately, and without a word, run back the other way at full speed. Boy, I sure wish I could do that now. I don't think I could run more than 20 yards at full speed without hurting myself.
I remember how puzzled and angry my mother would get when I got home, still dripping wet. I was a complete mystery to her in some ways.