There are many things I love about living at the beach, but one is the sea itself and its many moods. Sometimes the beach is covered in driftwood, while at other times the sand is swept bare. Every day is different.
It’s a long, gently sloping beach, which means that crossing to the water’s edge at low tide can mean an extra 100 to 150 metres walk, although the difference in height between low and high tide is generally in the region of 3 to 4 metres.
If Earth were perfectly round and completely covered in water, then high and low tides would be equally proportioned everywhere. But Earth is not a perfect sphere, and there are big continents getting in the way of water flowing and bulging in the direction of the moon. …
The sun has a part to play in tides as well. …
Wind and weather patterns also can affect tides. …
High-pressure weather systems can push down sea levels, leading to nice sunny days with particularly low tides. Low-pressure systems that lead to cloudy, rainy days often cause tides than are much higher than predicted, so watch out!
A few weeks ago we had particularly high swells and high tides, thanks to a New Zealand wide weather system. The sea scoured away the gently sloping foot of the dunes, leaving instead small cliffs of crumbling sand.
But even more, the huge tides tossed large tree trunks and other debris into the dunes. Some were a metre or more above the flat level of the beach.
Late yesterday I visited the beach 2 to 2.5 hours after high tide. I walked down the track through the dunes and stopped before I went down onto the flat part of the beach. The tide was still very high, washing up to within about 5 metres of the edge of the dunes. But there was quite a swell, and as I watched, a rogue wave drove right in and up to the edge of the dunes just below my feet.
These winter tides are tricky. I was glad I wasn’t walking dogs on the beach. It would be so easy to be caught out by rogue waves.
Here are a couple of interesting educational videos:
Earth didn’t have water when it formed, but it does now! How did it get wet?