I visited SIO briefly in the late 80s, and my most vivid memory is of a long haired dude in a Hawaiian shirt bursting into our meeting to announce "surf's up!", at which point everything stopped and everyone left. Back then it all seemed impossibly exotic to a PhD student from London.
As someone who recently started surfing, I understand the cultural timing a lot more now.
Good surfing requires pretty particular types of waves. Which in turn requires particular wind. Even at good locations, these are transient conditions that can appear and disappear at the whim of nature (even over the course of an hour).
Ergo, surf's up = drop things that don't need to be done ASAP
They'll be there later. Good waves probably won't.
Oof, those are some gnarly waves. Wave structure as a surfed experience is my favorite part so far: there are so many wave nuances I never noticed before.
Australian slabs - the big ones out of the polar south tend to have waves within waves and can even "triple curve" over; I'm in the west The Right (last of the three) was my local for a few years.