A wave breaking in front of you didn't start at the beach. It started as wind blowing across open ocean, often hundreds or thousands of miles away, days before it ever reached the coast.
It starts with friction
Wind blowing across open water transfers energy into the surface through friction, creating small ripples. If the wind keeps blowing, those ripples grow into larger and larger wind waves. Three factors determine how much energy ends up in the water: wind speed, how long it blows, and how much open distance — called fetch — it has to blow across uninterrupted.
From chaotic wind waves to organized swell
Close to the storm, the ocean surface is chaotic — waves of different sizes and directions overlapping. As that energy moves away from the storm, it sorts itself out. Longer-period waves travel faster and separate from the shorter, weaker ones, gradually organizing into the smooth, evenly-spaced groundswell that eventually reaches the coast.
The open-ocean journey
Once organized, groundswell can travel enormous distances with very little energy loss, provided nothing blocks its path. This is why a storm spinning far out in the Pacific can produce a clean, powerful swell on a coastline that never saw a cloud from that storm.
Where it finally breaks
A wave only breaks when it reaches water shallow enough to interfere with its motion — the wave slows down, the top outruns the bottom, and it topples forward. What the seafloor looks like at that moment determines the wave's shape entirely, which is why the same swell produces a completely different wave over a reef than it does over a sandy beach.
For how that seafloor shape actually changes the wave, see Point Break vs. Reef Break vs. Beach Break. For the full journey from storm to shore in one piece, see What Actually Happens Between a Storm Forming and a Wave Hitting the Beach.
We track the whole chain, not just the forecast.
Storm source, swell travel, and local conditions — all of it factors into whether we text you.
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