Biggest waves ever recorded in Sydney

Craig Brokensha
Swellnet Analysis

This week delivered one of the strongest East Coast Lows in recent memory, along with incredible rainfall totals and wave height measurements.

The NSW Public Works’ Manly Hydraulics Laboratory Wave Buoy - located about twelve kilometres offshore from Dee Why - broke a couple of records.

On Tuesday afternoon it measured its largest ever Maximum Wave Height, and it broke the record for number of hours the Significant Wave Height stayed above six metres. Perhaps most amazing of all was that it stayed anchored to the ocean floor and kept transmitting through nearly the entire event.

The record breaking wave was measured at 14.9m (Maximum Wave Height), and the sustained nature of the East Coast Low saw Significant Wave Heights - the average height of the highest third of all recorded waves - stay above 6m for an incredible 30 hours (the previous record was 24 hours).

Manly Hydraulics Laboratory provided the actual trace of this record breaking wave which you can see to the left. The measurement follows the buoy’s displacement from mean water level, rising up past 7m and then falling back past 7m below sea level.

Just an hour after this record-breaking Maximum Wave Height occurred, Significant Wave Heights were calculated at 8.1m, a 1 in 20 year event. The next comparable swell was back in 1997 and then before that 1974 - a year fondly recalled by older surfers.

Wave buoy data such as this is often recorded several times per year across Southern Ocean wave buoys (Cape Sorell, Cape du Couedic) during the biggest swells of the year, but such events are rare on the Australian East Coast.

Now with the rain clearing and the swell dropping, the fallout from this ECL on the coast and land is visible to all. Widespread coastal erosion, sand blown back into the suburbs, as well as flood and tree damage across the Sydney and Hunter regions. 

It'll take a while to recover but statistically speaking it'll be another couple of decades before we see anything of similar magnitude. //CRAIG BROKENSHA

The NSW wave data monitoring program is funded by the Office of Environment and Heritage.

Comments

surfstarved's picture
surfstarved's picture
surfstarved commented Thursday, 23 Apr 2015 at 3:16pm

Global warming is going to make a mockery of statistics Craig. $10 says it'll be much less than a couple of decades before we see another one.

Apocalypse when?

Don't let the bastards grind you down

Bargie's picture
Bargie's picture
Bargie commented Thursday, 23 Apr 2015 at 3:33pm

Not for a while ...
"from the latest report of the Intergovernmental Panel on Climate Change:
Some key passages:
On thunderstorms:
In summary, there is low confidence in observed trends in small-scale severe weather phenomena such as hail and thunderstorms because of historical data inhomogeneities and inadequacies in monitoring systems.
On heavy rain events:
In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale.
On cyclones and storms:
Over periods of a century or more, evidence suggests slight decreases in the frequency of tropical cyclones making landfall in the North Atlantic and the South Pacific… Several studies suggest an increase in intensity, but data sampling issues hamper these assessments… Callaghan and Power (2011) find a statistically significant decrease in Eastern Australia land-falling tropical cyclones since the late 19th century although including 2010/2011 season data this trend becomes non-significant ...
On extreme weather events:
For instance, evidence is most compelling for increases in heavy precipitation in North America, Central America and Europe, but in some other regions—such as southern Australia and western Asia—there is evidence of decreases.
On the warming pause, now 17 years:
The discrepancy between simulated and observed GMST trends during 1998–2012 could be explained in part by a tendency for some CMIP5 models to simulate stronger warming in response to increases in greenhouse-gas concentration than is consistent with observations… Almost all CMIP5 historical simulations do not reproduce the observed recent warming hiatus.

mick-free's picture
mick-free's picture
mick-free commented Thursday, 23 Apr 2015 at 4:04pm

Waste....could have parked itself 1000kms east.

I take 50:1 odds that the record won't be beaten in the next 30 years. I can send you my bank account details surfstarved

Mick Free FIFOFOMO

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Thursday, 23 Apr 2015 at 4:13pm

A bell curve with tails on the ends, like in asset pricing. Expect the unexpected.

Rabbits68's picture
Rabbits68's picture
Rabbits68 commented Thursday, 23 Apr 2015 at 4:19pm

Amazing!!! The beaches must be absolutely destroyed after that sustained onslaught!!

Crystal Clear

blindboy's picture
blindboy's picture
blindboy commented Thursday, 23 Apr 2015 at 6:23pm

Looks like serious damage with huge amounts of sand removed and steep erosion profiles running well past the low tide mark. I think it was the guy from Manly Hydraulic Lab on the News saying it usually took 10 months for the beaches to recover.......winter shorebreak anyone?

Rabbits68's picture
Rabbits68's picture
Rabbits68 commented Thursday, 23 Apr 2015 at 6:26pm

Thanks for that BB. Bummer!!

Crystal Clear

Adam L's picture
Adam L's picture
Adam L commented Thursday, 23 Apr 2015 at 4:41pm

Beaches down south had 6 to 10 foot walls of missing sand in places. Can't recall how high they were prior or how far they receded, but the fact remains...

donweather's picture
donweather's picture
donweather commented Thursday, 23 Apr 2015 at 4:57pm

"one of the strongest East Coast Lows in recent memory".....really.....the actual central pressure of the low didn't even dip below 1000 hPa did it? Wasn't it actually the large cradling high below it that did all the damage?

Craig's picture
Craig's picture
Craig commented Thursday, 23 Apr 2015 at 5:01pm

I didn't mention pressure at all Don. If I said deepest you could of picked me up.

Seeing the rainfall totals, wide-spread destruction and power outages as well as flooding along with some of the largest surf I've seen around Sydney, yes.

Speaking to a lot of older crew who've lived here for decades and they said they hadn't seen or been through anything like it.

donweather's picture
donweather's picture
donweather commented Thursday, 23 Apr 2015 at 5:07pm

So what made the ECL one of the strongest then? And usually, when one refers to ECL's and uses the words strongest, it kinda implies deepest....but I agree, you didn't use the word "deepest".

Craig's picture
Craig's picture
Craig commented Thursday, 23 Apr 2015 at 5:22pm

It's much like tropical cyclones, they don't reach any significantly low pressures but the meso-scale embedded lows and strong core wind speeds and gusts wreak havoc.

Here's some stats:

Wettest single day in 13 years for Sydney.
Wattamolla recording sustained wind gusts above 100km/h for 20 hours, peaking at 135km/h (73kts).
Strongest winds at Norah Head since 2007, the Pasha Bulker ECL.
3 deaths at Dungog as well as 4 houses washed away and 312mm or rain in 24 hours.
12 disaster zones declared across NSW.
200,000 homes without power.

Pretty full on event with even the premier telling people to go home early on Tuesday.
 

blindboy's picture
blindboy's picture
blindboy commented Thursday, 23 Apr 2015 at 5:14pm

I remember the 1974 storm. We stood on top of the headland between DY and Curl Curl and we could not see where it was breaking. I find it hard to believe that this one was bigger not least because, on the northern beaches at least, there has been less damage. In 74 waves were washing up DY Parade, nothing much has changed there, but it didn't happen this time.

many-rivers's picture
many-rivers's picture
many-rivers commented Thursday, 23 Apr 2015 at 8:39pm

Standing in the Harbord diggers car park , a left was breaking way way out from the headland and running into the bay at Manly. Freshwater was just white foam.This was a day or two after the peak of the swell I 'd guess.
Continuing up to Palm Beach we saw that the surf had washed over the sand isthmus and was washing the caravans ( yes there was a caravan park next to the golf course in those days) in to Pittwater.
There are plenty of photos around of what the wash did to the old baths near the Manly Ferry pier.

jules_w's picture
jules_w's picture
jules_w commented Wednesday, 29 Apr 2015 at 7:01pm

My folks have pics of Bilgola stripped completely of sand, down to large black rocks, post-'74 storms. They used to have a space in the Palm Beach Studios where apparently wash went across the road and palled at the doorway steps. Wish I was old enough to remember it (except then I'd be even older than I feel now!).

erikb's picture
erikb's picture
erikb commented Thursday, 23 Apr 2015 at 5:18pm

I went for a wave at bondi this morning and noticed what i reckon is a fair few meters additional drop from the promenade to the shoreline. Got a serious amphi theatre feel to it now..

Blowin's picture
Blowin's picture
Blowin commented Thursday, 23 Apr 2015 at 5:20pm

OMG the world is ending girlfriend !!!!

prawnhead's picture
prawnhead's picture
prawnhead commented Thursday, 23 Apr 2015 at 6:14pm

Craig , how much effect does the wind have on the buoys? I have noticed in the past that they can be showing swell on westerly winds and inshore conditions are not correlating with the amount of swell indicated, obviously there is sometimes more swell offshore than in close but sometimes the disparity in the readings and what is showing up on the shore is a bit different!

the_b's picture
the_b's picture
the_b commented Thursday, 23 Apr 2015 at 6:43pm

If ya ever fished out on the shelf 20-30kms out even in a 15kt westerly, you'll know it gets fuggen bumpy out there! 5-8kms out at the waverider in a 25kt westerly will def have a couple metres of sea.

stunet's picture
stunet's picture
stunet commented Thursday, 23 Apr 2015 at 6:34pm

Just had a session at my local beachie and can happily report that, while the storm surge washed over the beach through the carpark and into the beachpark, and the beach profile is as steep as I can ever remember seeing it, the inshore banks are fucking good. No conventional pattern to 'em, but waves were crossing the outside banks, refracting toward the beach in angular vectors of energy that combined into random and radical wedges. Like the best of D'bah on home turf.

Here's to the ECL!

mick-free's picture
mick-free's picture
mick-free commented Thursday, 23 Apr 2015 at 6:58pm

game on for you tomorrow then that new E swell is primo

Mick Free FIFOFOMO

blindboy's picture
blindboy's picture
blindboy commented Thursday, 23 Apr 2015 at 9:13pm

We seemed to be picking up some inconsistent but solid ENE action this afternoon at 3ft with a few bigger ones. There were reasonable waves but even an hour before low they were a bit fat. Hard to see there being much quality at all of it was any smaller.

Blowin's picture
Blowin's picture
Blowin commented Thursday, 23 Apr 2015 at 7:30pm

You guys are laughing.

donweather's picture
donweather's picture
donweather commented Thursday, 23 Apr 2015 at 8:31pm

My personal opinion is that this devastation on the southern flank of this low was due to the cradling high on its southern flank. BOMs 2007 summary of ECLs shows much deeper ECLs but fortunately very little to no cradling highs on their southern flanks.

http://www.bom.gov.au/nsw/sevwx/facts/events/june-07-ecl/index.shtml

mundies's picture
mundies's picture
mundies commented Thursday, 23 Apr 2015 at 9:03pm

I'm up on the northern rivers. No damage but great waves last few days. Stunet - when we have had big erosion events in the past I've noticed my local generally breaks really well. Clears out sand and the rocky contours underlying the sand seem to become more prominent with more defined banks in roughly the same position every time. Underlying bathymetry exposed by swell erosion...

mundies

thelostclimber's picture
thelostclimber's picture
thelostclimber commented Thursday, 23 Apr 2015 at 9:40pm

my local suffered some severe erosion, 2metre vertical drop to the beach now.
But there are banks every where.
Been waiting 2 years for banks like this.

carlton st's picture
carlton st's picture
carlton st commented Thursday, 23 Apr 2015 at 10:30pm

In '74 there were 8 foot waves that lifted 30 foot yachts into Balmoral baths, the Manly swimming enclosure next to the wharf was trashed overnight and Barrenjoey was nearly breached linking Pittwater with the ocean. 6th March '76 Doboroyd Bommie broke as a monster left from out off North Harbour right across to near Middle Head. It looked liked the Heads was closed out. I was surfing 8 foot "reforms" from that on Chinamans Point. This was not that big. Bah humbug

blindboy's picture
blindboy's picture
blindboy commented Friday, 24 Apr 2015 at 9:25pm

Ha Carlton I was out at Chinamans that day with Russell Lewis and Peter Crawford......a truly memorable experience!

carlton st's picture
carlton st's picture
carlton st commented Saturday, 25 Apr 2015 at 9:47pm

That was an interesting day it was bigger in the morning and cleaned up as the day went on. I remember Russell Lewis and the Dee Why boys were the A listers at the time and probably told Bruce Channon or Hugh McLeod about it as a few pics that ended up in SW.(A Swell to Remember) The big news was that Nat turned up late morning. It really is a novelty wave but he just ripped.

evosurfer's picture
evosurfer's picture
evosurfer commented Thursday, 23 Apr 2015 at 10:56pm

I was well and truly around in 74 and the reason so much damage was done back then was we had 3 giant storm surfs one after the other all within about 14 - 16 days. two from the south and one from the north. Completely changed the face of cronulla beaches nothing has even come close since. I will never forget the total destruction of cronullas foreshore.

IF im not surfing im racing

redsands's picture
redsands's picture
redsands commented Thursday, 23 Apr 2015 at 10:57pm

Impressive figures.I still believe August 1986 ECL was bigger and created larger waves.
It sat next to the coast for 5 days and then travelled e-ne and stalled in central tasman for a week creating two weeks of large surf.Anyone else remember?

wellymon's picture
wellymon's picture
wellymon commented Thursday, 23 Apr 2015 at 11:39pm

Yep.
3 days of super clean 6ft NW swell inside Cook Strait, unheard of as usually very short lived.
Also opened up some rare spots mid west coast Pig Island a very long right hander;)

Our brains are too small at the moment to comprehend the reality of what's happening in our forests . We're only just waking up so to speak . The big problem is we think we know everything, we are specks of dust on a timeline and we know nothing .

mick-free's picture
mick-free's picture
mick-free commented Friday, 24 Apr 2015 at 2:08pm

Pig island, there's no pigs out there.....shit would have been big!

Mick Free FIFOFOMO

wellymon's picture
wellymon's picture
wellymon commented Friday, 24 Apr 2015 at 3:02pm

Up Naki ways MagnetMick;)

Our brains are too small at the moment to comprehend the reality of what's happening in our forests . We're only just waking up so to speak . The big problem is we think we know everything, we are specks of dust on a timeline and we know nothing .

Zoooming's picture
Zoooming's picture
Zoooming commented Thursday, 23 Apr 2015 at 11:32pm

The wind may have blown hard and a stack of rain fell but where are all the pics of the action in the surf? Another ECL wasted. Would have been a different story perhaps with some west in the wind.

bmod's picture
bmod's picture
bmod commented Friday, 24 Apr 2015 at 8:27am

The '74 storm was definitely larger than the ones we have on record. I'm told there was a buoy that was in for servicing during the event so missed it all! Some work was done on back-calculating the wave height and it was estimated to have a Hs of around 10m. Often this is called a 1:100yr event, others suggest it was more like 1:1000.

Tide & Storm surge play a big part in erosion, the 74 storm (one of them) was on a spring tide, so together with the massive waves wrecked havoc. Its a number of months before beaches recover (sand gets pushed back onto the beach) so if we get another big one this winter there may be some trouble.

Great to read the first hand accounts of those big events!

redsands's picture
redsands's picture
redsands commented Friday, 24 Apr 2015 at 8:56am

http://forum.weatherzone.com.au/ubbthreads.php/topics/121653/1
This site has some info on the August 1986 ECL.Check out the synoptic situation around August 7-9 1986.

stunet's picture
stunet's picture
stunet commented Friday, 24 Apr 2015 at 9:37am

UNSW Water Research Laboratory has some great archive shots of beach damage from past storms:

http://www.wrl.unsw.edu.au/news/historical-coastal-storm-damage-photos-from-the-wrl-archives

Thanks for the heads up Blubber.

memlasurf's picture
memlasurf's picture
memlasurf commented Friday, 24 Apr 2015 at 4:41pm

Biggest waves ever for Sydney still seem almost standard fare on the Mornington Peninsula. You could never build a suburb like Manly that close to the water on the MP it would be regularly washed and blown away. I suppose it is called the Pacific for a good reason.

billie's picture
billie's picture
billie commented Saturday, 25 Apr 2015 at 6:44pm

I stood on the bower and watched Deadmans breaking for an hour and a half on Tuesday evening. Only one other car in the car park. It was so inspiring to see such beautiful, big swells.

I love storms and swells. We are so lucky to be surfers.

I have only been on the Northern beaches for five years, it was a buzz to drive around and see where all the deep bomboras live and hide.

Billie

mitchvg's picture
mitchvg's picture
mitchvg commented Sunday, 26 Apr 2015 at 1:31pm

Imagine copping that set, 1st wave the biggest haha. What was the period I wonder?

hrap's picture
hrap's picture
hrap commented Monday, 27 Apr 2015 at 10:01am

Hey craig, would you know what was the Hs of this time series where the 14.9 m Hmax was found? cheers

Craig's picture
Craig's picture
Craig commented Monday, 27 Apr 2015 at 10:50am

Hi Hrap,

Yes it was 7.5m..

hrap's picture
hrap's picture
hrap commented Monday, 27 Apr 2015 at 1:58pm

Thanks for the picture craig. That's practically a freak wave, which is remarkable for such a high spreading. Hmax steepness is also impressive. We might be looking to a very rare case!

Craig wrote:

Hi Hrap,

Yes it was 7.5m..

marcus's picture
marcus's picture
marcus commented Saturday, 9 Jan 2016 at 4:36pm

Hey ben and stu. I remember that 97 swell fondly. Had island to myself then luke matt and i checked a once secret spot at botany bay and sw what looked like bear island closing out accross most of the entrance on the northern side. A little gap on the ssouthern side. Biggest ive ever had outside island. I remember ringing the bouy hotline and it said 7-9m. Any chance i could get that old data? Matt hall doesnt believe me. Lol

i remember the internet when it was just for inteligent people

marcus's picture
marcus's picture
marcus commented Saturday, 9 Jan 2016 at 4:38pm

I think it may have been same day a cop and good surfer was ripped from point southies to greenhills and picked up by helicopter. Tho may have been a different swell

i remember the internet when it was just for inteligent people