Wave heights in Recent storms - Sean Porter

The following three images are of mean significant wave height derived from satellite altimetry. The first image, shows wave heights off the coast of southern Africa during the time a tropical cyclone coincided with unusually high spring tides (every 18.6 yrs) which as you know resulted in large seas that caused massive damage along the KZN coast last year in March 2007. Wave heights of approximately 6m were recorded.

The next two images show waves heights on the 31st August & 1st September 2008 during a major cold front event that passed over southern Africa recently. It is apparent from these images that the recent cold front event resulted in a much larger area of ocean experiencing anomalously high seas and waves heights far higher than the event in March 2007 on the KZN coast. Wave heights of 9.8 m can be seen off shore while wave heights of approximately 8.6 m were recorded on the Cape coast.

March 2007

September 2008

September 2008

Sean Porter
Marine Biology Research Centre
Zoology Department
University of Cape Town