Bathymetry
Also known as: Seafloor Depth, Ocean Floor Topography
Bathymetry is the measurement of depths and features of the seafloor — the underwater equivalent of topography. It controls everything about how an offshore swell transforms into a breaking wave: a steep drop-off creates heavy, throaty waves; a gradual shelf produces mellow, rolling surf; and underwater canyons or reefs can focus or scatter wave energy in ways that make one spot fire while the beach next door is flat. Swell Intel uses high-resolution bathymetric data for every spot to refract, shoal, and break offshore swell into realistic wave heights. Without bathymetry, a forecast is just a buoy reading with a pretty chart.
Related terms
- Breaking Wave HeightThe actual size of waves as they break at the shore, calculated from offshore swell and spot-specific bathymetry.
- Transect BearingThe compass direction a surf spot faces the open ocean, used to match swells to each break.
- Swell PeriodThe time between successive wave crests, measured in seconds. Longer periods mean more powerful, better-organized swell.