Seaside towns around the SA Coastline should be preparing for the weekend when extra high tides are expected along the SA coastline. Coastal fooding already occurred in the Strand area.
Image: Gordonsbay Security cam (Click on image for larger view.)
Image: Beach Road, Strand - Sandra Lizamore
At the moment several severe weather warnings has been issued for today and the weekend. People living near the sea have been advised to keep an eye out for changing conditions. Flood warnings has already been issued.
Higher than normal spring tides are expected this weekend. Spring Tide: 19 - 23 September 2013 are taking place close to the spring equinox on September 22. During an equinox the sun crosses the equator creating an extra tidal pull which could make already high tides even higher. Tides are expected to be higher than usual, however, if the high tides happen at the same time as high winds or storms, the defences may be unable to cope and some areas could end up flooded and under water.
Twice daily, the tide comes in, and each day it will be approximately 50 minutes later than the previous day. Astronomically, this is because as the Earth moves around on its axis every 24 hours, the Moon during the day and night moves through one-thirtieth of its orbit around the Earth. This means that it will be approximately one-thirtieth in a different position 24 hours later.
Tides are created by the pull of the moon and the sun on the world's oceans. The tidal force of the moon is greater than that of the sun, so the water on the side of the earth closest to the moon is pulled more strongly. As the earth rotates, different parts of the oceans are exposed to the moon, which is why tides ebb and flow.
When the sun is in line with the moon, the pull is greater so the tides are larger than normal. These are called spring tides and, despite the name, happen twice a month throughout the year. When the sun earth and moon form a 90 degree angle they work against each other causing tides that are smaller than normal. These are called neap tides.
The height of spring tides depends on the distance of the moon from the earth - the smaller the distance the larger the tide.
In September 2007 abnormally high tides caused by cyclonic activity, about 500km off the KwaZulu-Natal coast, the March equinox and the 18-year alignment of the sun, moon and earth, devastated homes, businesses and public infrastructure.
Not much can be done to stop the flooding, but plans are in place to deal with it and limit the damage it causes. Local authorities are on stand by and Disaster Management is ready to initiate its flood incident management procedures if necessary. These include issuing warnings, operating flood defences and, if necessary, evacuating people from the areas at greatest risk.
If the weather forecast does change, there are a number of precautions people living close to the sea can take. Moving valuable items upstairs, having sandbags ready and moving vehicles to high ground can all help limit the damage caused if flood defences are breached. Residents of coastal areas should remember to keep an eye on weather forecasts this weekend
Beware of high spring tides, rough seas and high swell over the
next couple of days.
- MSBWX
