The KwaZulu-Natal and Eastern Cape coasts have experienced unusual tidal activity and sea currents in the wake of the earthquake that struck south-east Asia at the weekend which sent giant waves across large areas of the Indian Ocean.
In the Port Elizabeth area one person is missing, believed drowned, as a result of higher than usual swells, but by Tuesday the muted effects of the 9.0 magnitude earthquake on South Africa’s coastline had largely subsided.
Commander of Port Elizabeth’s National Sea Rescue Institute (NSRI) Ian Gray told Sapa there had been a ”phenomenal tidal variance” in Algoa Bay on December 26.
This had prompted the NSRI to issue a warning for the coast west of Port Elizabeth.
”The sea was rising and dropping two to three metres outside the normal tidal variance,” Gray said. The tidal cycle had also been affected.
”What usually takes 12 hours (between tides) was happening in 20 minutes.”
There were also larger-than-usual swells, which had flooded some quays and swept across local beaches.
Three people had been washed out to sea by a high swell at Blue Horizon Bay on Sunday. Two were rescued by members of the public, but a search by the NSRI had failed to find any trace of the third, who is presumed drowned.
Gray said that at one stage the longshore current off the bay appeared to have reversed.
From Durban, NSRI duty officer Alan Cutten said the KwaZulu-Natal coast had experienced some ”unusual tidal activity”, and in the channels around Durban harbour current speeds had increased.
By Tuesday, these phenomena had largely subsided.
In East London on Sunday afternoon the Buffalo River rose about three metres above its normal level, causing yachts to break their moorings.
”There was a major surge up the river on the high tide, and seven yachts broke their moorings and were drifting around. We had to go out and secure them before they got pushed under the bridge and snapped their masts,” said East London NSRI station commander Geoff McGregor.
There had also been unusual 20-minute tidal surges, which were still happening on Tuesday, but appeared to be subsiding.
”There is no danger for bathers,” McGregor said, while on a beach inspection.
The SA Maritime Safety Association said on Tuesday it had issued no general warning to local shipping in the Indian Ocean. – Sapa