Swell
Topic: Movements of Ocean Water: Waves, Tides and Currents · NCERT: Class 11, Ch 13 "Movements of Ocean Water"
Meaning
Swell is made of long, slow, regular waves that have travelled far from the storm that raised them. The storm may be thousands of kilometres away, sometimes in the other hemisphere. As waves travel, the short, choppy ones die out, and the long, smooth ones carry on. So swell can reach a coast even when the local weather is calm. Steep, short waves, on the other hand, are young waves raised by the local wind.
Example
Long swells from storms in the far Southern Ocean reach the Kerala coast on the Arabian Sea. They can cause sudden coastal flooding called Kallakkadal, with no local warning.
Don't confuse with
- Wind waves (young waves): steep, short and irregular, raised by the local wind at that place. Swell is long and regular and comes from far away.
Related concepts
- Wave
- Orbital motion of water particles
- Fetch
- Wave height
- Wavelength
- Breaking of waves
- Longshore drift
- Kallakkadal