Meteorology · Waves — Shoaling and Refraction
As swell moves from deep water into shoaling water near a coast, the waves:
- ADisappear entirely
- BSpeed up and flatten
- CSlow down, shorten, and steepen, eventually breaking, and refract to align more parallel to the depth contours✓ Correct
- DReverse direction
Explanation
In shallow water the wave feels the bottom, slows, shortens, and steepens until it breaks. Refraction bends the crests toward alignment with the depth contours (and concentrates energy on headlands). This is why surf and dangerous breaking seas form over shoals and bars.
Authority: Bowditch (Pub. No. 9), Waves
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