From the ABC
Monster 23.8m-wave is largest ever recorded in southern hemisphere
A wave-measuring buoy in the Southern Ocean has recorded a massive 23.8-metre wave, according to New Zealand meteorology and oceanography consultancy.
“This is a very exciting event and to our knowledge it is the largest wave ever recorded in the southern hemisphere,” MetOcean Solutions senior oceanographer Dr Tom Durrant said.
The mammoth wave, which formed during a storm, dwarfed the previous record of 19.4m measured by MetOcean Solutions in May 2017, as well as a wave recorded in Australian waters in 2012 that measured 22.03m.
The solar-powered buoy, moored near New Zealand’s Campbell Island, only records wave heights for 20 minutes every three hours.
Because of this, Dr Durrant said it was “very probable” even larger waves could have occurred during this storm.
But storms such as this have do not just affect coasts in the Southern Ocean.
“The persistent and energetic wind conditions here create enormous fetch for wave growth, making the Southern Ocean the engine room for generating swell waves that then propagate throughout the planet — indeed surfers in California can expect energy from this storm to arrive at their shores in about a weeks’ time,” Dr Durrant said.
“[This] storm is the perfect example of waves generated by the easterly passage of a deep low-pressure system with associated wind speeds exceeding 65 knots.
“Such storms are frequent and can occur at any time of the year, which differs from the high-latitude northern hemisphere storms that only occur in winter.”
Dr Durrant said what makes this storm particularly interesting is that its speed appears to match the wave speed, which he says allows wave heights to grow dramatically.
Significant wave height is the value used by the World Meteorological Organisation (WMO) to characterise sea state, MetOcean Solutions said.
“During this storm, the significant wave height reached 14.9m. This is also a record for the Southern Ocean, but falls short of the 19m world record buoy measurement that was recorded in the North Atlantic during 2013.”