January 25, 2002
If you are a surfer, Hawaii has about everything you need, and in particular, big waves. The beaches on the north shore of Oahu have the reputation as the world's best for big wave surfing. Not only are the waves reliable, but the configuration and geometry of the shore guarantees that the waves that come ashore there will be bigger in comparison to most sandy beaches. Other than the shape of the shore, the three main factors that determine the size of waves are wind speed, fetch and the duration of the wind. Since Hawaii sits pretty much in the middle of the Pacific Ocean, it has a tremendous fetch, regardless from which direction the wind is blowing.
On January 28, 1998, a powerful extratropical storm generated monster waves in the Hawaiian Islands. This storm generated swells (long period waves) that were 9 m (28 feet high) in the open water between Japan and Hawaii. When these waves reached Waimea Bay on Oahu's north shore, they rose to 13 m (40 foot) behemoths! The wave faces were in some cases 26 m (80 feet) - the slope distance between the crown and the wave trough. The "tubes" or tunnels created by such huge plunging breakers could have swallowed a bus. Interestingly, when the waves from this storm finally reached Hawaii, the skies were clear and the winds were nearly calm.
January is the time of year when the biggest waves are most often seen on Oahu. Big waves can come in at any time of the year, but since extratropical storms are most prevalent during the winter, this is when the biggest waves are most often observed.