Same thing happened boxing day tsuami. I seen 3-4 tidal surges in the same spot at rotto 20mins apart. My boat went to laying on its side as pictured then high water mark lapping up to the shrub line on the beach.  Very strange for us as the news had not hit us at rotto regarding the tsunami.

 Just had another one but half the movement.

 There have been a few very large quakes around the world in the last week, betting there was an undersea slip somewhere that sent a small Tsunami surge. And the fact it happened twice. 

http://At least five processes can be involved in altering tide levels during storms: the pressure effect, the direct wind effect, the effect of the Earth's rotation, the effect of waves, and the rainfall effect.[10] The pressure effects of a tropical cyclone will cause the water level in the open ocean to rise in regions of low atmospheric pressure and fall in regions of high atmospheric pressure. The rising water level will counteract the low atmospheric pressure such that the total pressure at some plane beneath the water surface remains constant. This effect is estimated at a 10 mm (0.39 in) increase in sea level for every millibar (hPa) drop in atmospheric pressure

Could be Tsunami, or maybe the above , this low pressure system came barrelling directly down the west coast this morning running paralell with the land.

Can they maybe suck the water in towards themselves, and therefor dropping the water in front of it were you are in Rotto?.

 Yes very similar to what happened when I was on dunsborough beach Boxing Day tsunami.

Well we were diving out there today, and it wasn't good haha i did see your boat on the way past !

 Transport department Fremantle fishing boat harbour graph has a clear spike and drop mid afternoon to reflect what you said. Has to have been a storm surge.

 Going from what Rob said, it went in and out several times, exactly like a tsunami. Did it in the river at Kalbarri during the Boxing day tsunami, three major level changes in 45 minutes. I'd be very surprised if it was a storm surge, they usually just come and keep coming until they recede. And atmospheric conditions will certainly affect sea levels, but not in an in/out fashion. 

 Yeah. Couple of boat sunk in the Gero tsunami too if I remember correctly.

If a submarine was belting in to garden island would it displace this amount of ocean

 lol or maybe a large krakken

 It was us mate, we loaded all your prawns n crayfish back on the searcher and put her in the drink. Surely enough weight there to effect the water levels!!!

itic.ioc-unesco.org/index.php

www.bom.gov.au/tsunami/about/atws.shtml

Just seems odd , that with all these resources , and tax payers money I might add , no reports , nothing

Theres seems to be shortage of pencil necks just hanging for something to happen , and yet they said zero.

And yes upon re reading your report , it doesnt seem like storm surge, so let the theorys begin!

My top two are, the aliens that swallowed that maylasian plane just left earth, and Lizzy quay is that deep ( designed by engineers remember)

that when filling it , it dropped sea levels everywhere!

The Australian Government committed $68.9M over four years to establish an Australian Tsunami Warning System by 2009. This included: Establishment of the Joint Australian Tsunami Warning Centre (JATWC) with 24/7 monitoring and analysis capacity for Australia; The upgrade and expansion of sea-level and seismic monitoring networks around Australia and in the Indian and South West Pacific Oceans; Implementation of national education and training programmes about tsunami; Assistance to the Intergovernmental Oceanographic Commission (IOC) in developing the existing Pacific Tsunami Warning & Mitigation System (PTWS) and establishing an Indian Ocean Tsunami Warning & Mitigation System (IOTWS); and Technical assistance to help build the capacity of scientists, technicians, and emergency managers in South-West Pacific and Indian Ocean countries. The project was completed successfully in 2009. Australia now has a world class tsunami warning system providing 24/7 monitoring, detection and warning services for Australian community.

www.transport.wa.gov.au/imarine/rottnest-island-tide-and-wave.asp

Click on the significant wave height graph header.

I am reading it as a 1 metre rise in seas followed by a drop , with no rise in swells, odd and potentially dangerous.

 Storm surge related to the intense thunder storm cells in the area. I've seen this before with similar tidal ranges at Hillaries before.

 Not a U.S. Submarine then LoL

 Could it be related to a grain spill in the sound? 

Just a thought, when the last ship drifted into the Railway bridge, it was due to a 'sudden' storm surge the official incident report claims.

Dropped our boat so that the chine got below the jetty deck that we tied to, and then came up so fast that it almost trapped the boat under the edge over the chine. We weren't even contemplating this sudden change and if not for some good spotting by the friends we were picking up for crabbing, and then some hasty pushing the boat easily could have been flipped like the one in Gero. We had to get 10 people on the Starboard side (the one we tied to the jetty) to free her.
We got underway but the rise and fall in the level freaked out an Ex Pro Crayskipper and he just wanted to beach the boat and run for high ground. I recall so well his WTF face as we came out of the canals and the tide turned again running fast out, then fast in.
So with that change I would say mini-tsunami as the cause.

Just looked for any information relating to a tsunami in the Indian ocean over the weekend and cannot find anything though did see that on Sunday, one page shows a 2.3 around York way on the 31st and there was a 4.6 in Timor. Generally there would be a news report if something was felt within the state.

Another page shows nothing in the Indian ocean area for weeks so take from that what you will.

What time did you experience the surge?

Had one over at Red Cliff bay on Bernier island about 7 years back, sudden surge as the clouds passed over then water level dropped by over a metre resulting in 4 of the 5 yachts anchored there nearly being swamped when the surge came back in. Or then local meteorologist was there and took photos showing much the same effect as the ones above

 gee, if that was any form of tsunami i dont hold much faith in early prediction if one heads our way. i notice the ferry in the background wonder how they went tied off to the jetty

 Was working on a boat in two rocks on the day and remember about 1-2pm thinking the tide was really horsing out with little eddies forming as it went past the rocks near the cray shed. Later that arvo i was looking at the same area and thinking the tide was still horsing out and that was a bit strange as the boat had not dropped much in relation to the jetty. Tsunami for sure if it was going on at rotto also.

 I've never personally seen a sudden change and reversal of depth from passing weather, particularly if it repeats a number of times, but i certainly don't know everything. In fact, the older I get, the more i realise how little I  know

Very interested to see what geoscience have to say about it.

Hello Rob,

Thank you for your email dated 01 Feb 2016, concerning sea level movements at Rottnest Island.

An investigation has indicated that no tsunamigenic earthquakes were recorded at the time that may explain your observations, so it is unlikely the anomalous sea level heights were from a tsunami generated by an undersea earthquake. However, a “meteotsunami” may be the likely explanation for the water level movements you observed.

An intense low pressure system passed over the location at the time of your observation. Fine-scale features of such atmospheric disturbances, which are hard to predict and monitor, can generate sea level anomalies that behave and look similar to undersea earthquake generated tsunamis. A link to a recent paper discussing meteorological tsunamis (meteotsunamis) in south west Australia is included for your reference http://link.springer.com/article/10.1007%2Fs11069-014-1263-8 .

We are certainly looking into how we may forecast meteotsunami effects, but the science and lack of detailed observations offshore pose challenges.

regards

Brendan Casey

Coordinator Tsunami Warning Services

Australian Bureau of Meteorolo