Storms & More Erosion

The past few weeks has seen more erosion along the Venus Bay beach in many locations. The profile of the upper beach is also steeper (more the classic winter berm) in front of the recent erosion. The erosion scarps are up to 3m high, probably the highest this year.

These are classic features of low pressure (storm surge) corresponding with higher tides and strong on-shore swells. You’ll see the sand is still there, as a wider beach and sand bars at low tide.

Still Eroding

 

Having been away for a couple of what I have come to know as the most active erosion months (August and September, presumably because of the strong swells and storms are common in these months). I was surprised that maybe there had not been as much erosion as I was expecting. Still quiet a lot of the beach shows an erosion scarp of 1 to 2m. I was also surprised to see so much seaweed on the beach (perhaps the swells have also disturbed the kelp forest off shore).

This location (just south of the beach one ramp) also shows clearly something I had noted before. The fenced “rehabilitation” area, has mainly coastal spinifex, where as the eroded area to the south is dominated by marram grass. Perhaps the flatter slope angle of the dunes with coastal spinifex lets the occasional high waves run up their surface rather than starting an erosion notch.

Bigger swells and more dune erosion

I was keen to have a look at the beach and see how the big swells of last week, affected the beach. Swells bought to our coast by really big storms and heavy weather in the southern oceans. The surfers where disappointed because the winds where not off shore, to lift the waves, but the strong on-shore winds made matters worse for erosion, that push the water up against the coast even more and clearly helped the swells and waves they produced reached right up to the dunes. Even though we not quiet to the full month.

The result is a lot of new erosion, not everywhere but obvious all along the beach.

Foam & More Foam

Today the swells as pounding in, the wind almost gale force but the waves do not appear to be eroding the dunes (they might tonight with a high tide corresponding with a low pressure and very strong onshore winds). What is most amazing is the surf foam racing across the sand and on up the dunes.

Taking on the winter shape…already

The beach is loosing the distinct flatter area of dry sand from the upper beach zone and a continuous sloping curve, typical of the winter shape (or winter berm) has quickly developed for the beach profile. The reason is clearly the strong onshore winds, strong swells and powerful waves crashing onshore. The highest tides are however not reaching the scarps from previous erosion.

In previous years these changes have more typically occur in April/May.