rsbm....[/I]
Metic kindly presented sea conditions taken from Albany and the Rottenest Bouy 4 km west of Rottnest without indicating swell direction which is extremely important as because of Rottnest Island is the barrier for the swell and has little relationship to what occurs on Cottesloe beach.
Weather on Sunday 19th June 1988 was 19 degrees and rain. (Sunday Times 19th June 1988 Murder Hunt Car Clue) Not bad for winter and corresponds to the image on Cottesloe beach approx 7.00 am June 1988 with the older lady swimmers. Notice how many people on the beach around 7.00 am in winter in June 1988. (prvious post)
JC went missing that night, 12.30 am on the 20th June 1988. The back seat of the Fiat washed up on the afternoon of 20th June 1988.
Waves on Wednesday 22nd June 1988 can be seen and they may be 0.5 m. when the image of the car was finally shown in July 14 2000.
Picture of Cottesloe beach on Friday 14th June 1988 looks stormy and rough from the image. However, there the car was retrieved two days before this and even though this is the big storm, there were no waves breaking over the groyne.
The Daily Mail Friday 24th June 1988
Notice the subheading that hotels worry that a maniac is stalking Perth's women.
Repost::
Physical oceanographer
On the swells direction :
" around *287.5, degrees
then jumps/spikes to *319
and *343 degrees or so ."
*important ! See compass .
Rottnest island doesn't create a major swell shadow on Cottesloe beach during west-north-west swell events .
At rare times most likely in winter the waves will go above 2-3 metres at cott & metro beaches .
So far during 2017 , there has not been a swell event in WA as big as the event 17-19 june 1988 !
Indicating just how rare it is ,
It may not occur every year .
This was a remarkable swell event way back in june 17-20th june .
Plus in the early AM hours of the 22nd june another dangerous swell event was recorded with a massive 22 second period.
Although not tall, these waves were moving twice the average wave speed . These conditions are the deadly type of waves that wash rock fishermen into the ocean / & drowned .
Articles links have been supplied about this.
http://www.websleuths.com/forums/showthread.php?p=13393864
http://www.websleuths.com/forums/showthread.php?p=13393776
"Swell was quite west as expected " quote po
Cottesloe beach geographical location is exposed to swells from this direction ie ; Swell angle of northwest :
Physical oceanographer
On the swells direction :
" around *287.5, degrees
then jumps/spikes to *319
and *343 degrees or so ."
*important ! See compass .
Cottesloe beach geographical location is exposed to swells from the Swell from the northwest :
These swells may be truly from a west or wsw direction .
They then refract around the Northside of Rottnest .
The west side of Rottnest was 5 metres decreasing and a few hours later cott educated guess ; 2.5 metre because;
The swell was able to bypass around the northside of Rottnest island .
Rottnest doesn't create a major swell shadow on Cottesloe beach during west-north-west swell events .
Wave height and power is lost as the swells travel over shallow water .
This is called 'wave attenuation due to bottom friction'
Only at rare times will the waves will go above 2-3 metres at cott metro beaches .
So far during 2017 , there has not been Any swell event in WA as big as the heights recorded 17-19 june 1988 ! (according to dotr buoy data)
It may not occur every year , this was a remarkable swell buoy reading .
http://www.websleuths.com/forums/showthread.php?p=13393992
During the time frame of 1am - until mid morning on the 20th june the waves would still have been big (for cott standard) imo .
Theres also a window during the early morning hours on the 22nd june that the waves may have had the power to damage, accident or drown whatever etc it may have been .
swimming conditions were fine on the 21st absolutely.
See link and graph of the frequency ,
This is when a 'long period swell' arrives
