Cape records highest wave in 39 years
A record-height wave was recorded during the severe storm which battered the Western Cape in June.
The Council for Scientific and Industrial Research (CSIR) says it recorded the wave during the storm on Wednesday 7 June.
It had been recorded south-west of Kommetjie in Cape Town.
The council says the unusually large and violent storm resulted in wind speeds exceeding 120 km/h, with significant wave heights of up to 11 metres.
CSIR coastal technologist, Sarel Haasbroek, says that there is only a 2.5 - 3% probability per year of a similar wave event occurring.
"The number of these wave events occurring in the next 30 to 40 years is one. CSIR engineers have confirmed that this was the largest wave event recorded since 1978 when a single wave reached a height of 20.5 metres, the approximate height of a seven-storey building. This record was captured west of the Cape Peninsula," Haasbroek says.
The CSIR recorded similar but slightly lower wave events in 2001 and 2002.
Haasbroek says the storm which hit the Cape on 7 June was an extraordinarily large storm produced by exceptional conditions.
During the recent storm, an extreme long-wave height of 0.7 m was recorded at the Container Terminal in Schoeman Dock, in the Port of Cape Town.
The CSIR says although this may not seem to be a very high wave, it was the biggest long-wave condition recorded in the Port of Cape Town to date. Such long waves may lead to water resonance and in turn cause ships to part from their moorings.