The low pressure system that impacted the west coast of the United States over Thanksgiving was generating monster waves rarely observed on the high seas.
The wave heights were recorded by a Coastal Data Information Program buoy located off Cape Mendocino in northern California on November 27th, as a strong Pacific storm approached the U.S. West Coast.
According to the data, one wave was observed to be a whopping 22.7 meters, or 74.4 feet tall.
The storm that impacted the California coast last week generated some of the largest waves ever recorded by CDIP buoys. At Cape Mendocino, CDIP staton 094, the significant wave height was 13m/43ft and the largest wave measured was 22.7m/74.4ft!https://t.co/FeUStWsF9A
— CDIP Buoys (@CDIPBuoys) December 2, 2019
While significant wave height at the time was just 13 meters (43 feet), the observed wave goes to the show that individual waves can reach heights much greater than the surrounding sea state.
Significant wave height is recorded as the average height, from trough to crest, of the highest one-third of all waves measured, so individual waves can be much, much taller.
While large, significant wave in the 13-meters range are not entirely uncommon for parts of the Atlantic and Pacific.
In 2016, an expert committee convened by the World Meteorological Organization established a new world record significant wave height of an almost-inconceivable 19 meters (62.3 feet) measured by a buoy in the North Atlantic. In 2017, a hurricane-force low-pressure system in the northwestern Pacific Ocean was observed by satellite to be producing significant wave heights of 17.6 meters. Generally, waves of this magnitude are typically measured by satellites using altimeter instruments, rather than by surface buoys.