Graham Easterling wrote:

On Sunday, December 31, 2017 at 1:04:58 PM UTC, Norman Lynagh wrote:
These waves were videoed a few days ago at Cape Verde. It shows the
power of long-period waves even though the height is relatively
modest. I make the period something like 13-15 seconds

https://twitter.com/twitter/statuses/947449527065305088

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
Twitter: @TideswellWeathr

Demonstrates nicely that size isn't everything!

Graham
Penzance

Over the years I have spent a considerable amount of time educating
people, who should perhaps know better, That the most important factor
in the movement of large ships, both offshore and in port, is the wave
period. Increases in the period are far more important than increases
in the wave height.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
Twitter: @TideswellWeathr