Comment by purplemoonx

It changes constantly on a daily cycle and also on a larger seasonal cycle.

Slope defines the water depth and what kind of beach it is - long flat beach means shallow water, steep beach means deep water - it affects if you can you fish there, route lagoon systems and seasonal floodwater, do sports like surfing and skimboarding which are highly dependent on it to the point you can only do it some times of day only part of the year, and other things like whether or not it’s safe to be on that day for visitors.

In California, a beach can be flat and inches deep in the Spring at low tide, and be 20ft deep in Winter at high tide with a massive hill you can’t even stand on with basically a river running thru it. That same massive hill can turn into a literal cliff drop off 25ft to a flat beach below overnight. So you come back 24h later and it’s a massive cliff now. Come back 8 hours after that and it’s like a massive flat puddle revealing hundreds of yards of exposed land.

It’s not random either, it happens in cycles that you observe if you go there daily to fish or surf, but none of the weather or surf apps can ever predict it.

A great example is the amazing skimboarding conditions in Laguna Beach and Santa Cruz during the fall (October, November) there's nothing like it anywhere else in the world.

Another good example is surfing the winter swell in Santa Cruz, when a good majority of the beach disappears underwater for months. A wave you're surfing on Halloween is where someone will be laying out tanning in June.