Notes From A Swell To Remember
Notes From A Swell To Remember
Is it better to undercall or overcall a swell?
What if that swell was already in the top 5% of swells that break on a certain coast? Does it matter then?
Many questions, no certain answers, as we hindcast the swell that struck the lower NSW coast this week. As I write, the waves are 10 feet at the local pointbreak but they’ve come off the boil from this morning, and they're significantly smaller than what was seen yesterday afternoon when all hell broke loose.
The low that created the swell was always going to be a good one, but ‘hell breaking loose’ wasn’t what we were expecting…it wasn’t what anyone was expecting. So let’s take a look back and see what happened.
Tuesday morning and Riley Pitt freefalls onto the foam in Sydney's Eastern Suburbs (Dimas De Novais)
Last Wednesday’s NSW forecast made mention of a trough moving offshore on the coming Sunday, dragging with it in-feeding north-east winds. The trough itself wasn’t expected to amount to much, therefore the forecast was for north-east swell on Sunday tapering through Monday and Tuesday.
In typical East Coast fashion that forecast changed radically from Wednesday to Friday as all models pointed towards a significant low spawning off the trough. Forget the north-east swell - though it’d still be in the water - the predominant feature would be a south-east swell off the suddenly-announced low.
The low had tropical origins, and as a consequence was loaded with moisture. An active phase of the Madden Julian Oscillation (MJO) spawned an inland tropical depression - which has brought devastating flooding to central Queensland - with the depression drifting south-east across New South Wales before moving offshore on Saturday evening.
A classic Tasman Sea Onion; a shape that sends East Coast surfers spiralling
When the depression deepened into a Tasman Low the forecast was bang on track. Strengthening north-east winds from the Coral Sea brought building levels of swell from the same direction as winds went slack into the afternoon. The waves were playful and fun.
This swell strengthened further through Sunday as the low started to take shape, however there were underlying signs of what was to come. To varying degrees, all the popular wave models showed in-feeding north-east wind creating mid-range head-high north-east swell, overtaken by a large south swell near dark.
Instead the predominant swell - at least for the Illawarra and Sydney - was a mix of E/NE and E/SE swell that pushed north of six feet, even up to eight feet at select spots, for a few hours on Sunday afternoon.
The takeaway from that? The winds feeding into the low were stronger than what any of the models had progged. In hindsight, that was the first sign the low might punch above its weight.
Yet all of Monday there was no sign that it would. The swell angle shifted a bit more towards the south but there was no upwards rush in size, just a general spread of six foot-ish swell from sun up to sun down. Our Monday forecast was for 10-12 foot surf on Tuesday and there was no reason to believe otherwise.
Dawn on Tuesday revealed an on-point forecast: 10-12 foot waves at all exposed reefs from the Sapphire Coast to Newcastle. Though from the southern quadrant, the wind had just enough west in it to make the lee side pointbreaks and reefs pump. It’s not unusual for this coastline to get 10-12 foot surf, it happens a few times each year, yet to have the winds co-operate put it into a special category - a day not to be missed.
In the Swellnet office, however, we’d seen the most recent ASCAT passes of the low pressure system (ASCAT is a low-orbiting satellite that measures ocean winds in real time). What we saw was something else again: a deep cyclonic-shaped ‘eye’ with a broad field of storm-force winds pointed directly towards the lower NSW coast - see below right.
At left, with spiralling arms, the satellite image of the low isn't unlike that of a tropical cyclone. At centre, the ASCAT reading shows strongest winds off the low's south-west flank directed towards the NSW coast.
It wasn’t an East Coast Low, it formed too far offshore for that, the coast wouldn’t feel the destructive winds, they were building far offshore, giving time for the resultant swell to stretch out in period, groom itself, and spray a wider range of coastline.
By midday Tuesday it was clear the swell had been undercalled. Calls around the grounds were quoting 15 foot sets at deepwater reefs with hesitant answers pushing even further north. 18 foot? 20 foot? Can you say that on the East Coast..?
Surfers might waver but the numbers don’t lie. At 1pm Port Kembla buoy struck 6.7 metres with a period of over 15 seconds, and it was coming from the east-southeast, which means pretty much square on.
We’re not going to reference all the sessions that went down in protected corners, mysto reefs, or simply out front if you lived near Ben Buckler. If you got in the water, felt it, then we’ve no doubt it was a day to remember.
Chase Hardaker on what may become the defining wave of the swell at Ben Buckler (Orlanda Golfin)
2:35pm Tuesday from Swellnet's Cronulla Point cam. The point can hold 10-12 feet fairly easily, yet it became a mere shorebreak to Phantoms, the bommie that sits north-east of Shark Island and which pulsed with long lefts of indeterminate size, swamping the Island and sending weird reforms into the point.
So what happened, we can hear you ask.
From Wednesday to Friday the forecast changed markedly - which rings alarm bells at the forecast desk - but then it settled towards Monday’s forecast. Good 10-12 foot surf is a rare thing and not a prediction taken lightly. To go above that size is risky - we’ve all felt the disappointment of a system downgrade.
A matter-of-fact explanation would point at the tongue of 26°C water that’s currently pushing as far south as Jervis Bay. That warmer than average water provided the catalyst for an unforeseen intensification of the Tasman Low through Monday afternoon and night.
Warmer water provides more potential energy to the low through evaporative processes, and when combined with the already loaded tropical system, resulted in one of the strongest Tasman Lows we can remember.
While we have the lab coats on it’s worth pondering why the swell didn’t reach the NSW north coast. We’ve already mentioned ASCAT readings, yet some of those showed storm-force winds pointed further north suggesting Ballina and Byron, and perhaps even the Gold Coast might get something substantial.
It wasn’t to be with southerly-exposed spots at Ballina reaching only four feet. A hypothesis is that, while the low was very well positioned for the lower NSW coast, it only briefly cycled through a stage of good winds for further north. Sure, the ASCAT looked promising but that’s a mere snapshot.
Any other working hypotheses are welcome below the line.
// SWELLNET
Comments
Shit a brick!
That was one hell of a low!
Jeezus!
I look forward to the footage.
Aloha Nui Aoi boys.
As Duke once said "Don't worry...wave come.."
Sure did!
and this is one of the many reasons we love Swellnet.
Agree Gra, fantastic explaination.
Great read Stu but as far as I'm concerned this low still has some 'splaining to do.
As well as producing an XL swell for Southern/Central NSW this swell should have also been a banger for regional Points in Northern NSW- as per other analogue systems.
Here is a storm force low, which formed Aug '21 and generated 15ft+ surf for Wedding Cake Island.
Swell went from flat to 6ft here in about 3hrs that afternoon (see below).
Next morning, fully pumping 6ft+ point surf. (see below).
This current low was stronger, better positioned and produced arguably bigger surf across Southern/Central and Mid North Coast NSW.
Yet we got this out of it.
Not even the biggest S swell this year- that occurred on 17Feb.
A few bigger sets showed this arvo but still, an epic fail for such a beast of a low with storm force winds in the central tasman.
Maybe the offshore bathymetry between the point and the river is loaded with sand
Possible all time phase coming up when it shifts
It's a head-scratcher all right. No solid theories from me. Even the one I offered - brief ASCAT pass - should've, with a 50-55knt wind field, delivered something more than that brownwater gurgle.
I'd take Supertubos over that.
Any chance that unusual southbound currents could have played a role? Similar to when an outgoing tide stops the swell from coming in.
Yeah, the swell has to travel against the EAC, effectively twice as far or more perhaps. All sorts of processes going on.I wouldn’t want to have been sailing around out there, could have been a zone of huge standing waves and triple ups no one saw.
Where is this!!
You don't know Burleigh Heads??
Lennox
Haha, fuck you’re a genius!
I find it quite weird too Steve. My zone on the MNC misses a lot of S swell, but has been fairly macking the past 2 days. Most often the case is it can be more or less unrideably flat on a S swell, only to see the LeBa region pulling in 6-8ft of swell. Got no answers for ya, but I'm certainly not complaining.
How’s the speckled cloud on the satellite image
That’s a snow bearing front if it comes through the Bight
Must have been a big mix of cold and warm
Latest Bom climate notes are pertinent.
Sea surface temperatures (SSTs) in the Australian region during February 2025 were the warmest on record for all Februarys since records began in 1900. Monthly SSTs in the Australian region have been the warmest on record for each respective month since October 2024.
The latest weekly SST analysis shows warmer than average waters around most of the Australian coastline, reaching up to 2 °C above average off much of the western and southern coasts of Australia, and in parts of the Tasman Sea. Oceanic heat is returning in the Coral Sea following a temporary cooling influenced by Tropical Cyclone Alfred.
Warmer than average SSTs provide increased atmospheric moisture and energy that can influence the severity of tropical storms and weather systems and support the genesis of tropical cyclones.
Don’t forget the fish! Saw a post the other day about Wahoo being caught as far south as Eden. Crazy how far south that warm water is extending.
Yes, this certainly caught my attention when I read it the other day. I wonder if it means Autumn will be pretty much non-existent, rain and humidity all the way through until June and then the massive highs that have become such a feature of our weather, takeover.
If that bomb of Chase Hardaker's isn't 20foot (at least) then i don't know what is.
Wowee!
Great read and loving hearing all the stories.
Besides the height. Look at how much ocean is in that thing! Crazy wave and photo.
Somebody give that man the wave of the swell trophy. It's an iconic, historic moment
Well spotted. Hats off to all out there.
Great idea, all we could give him is a nomination...for
Swellnet Charger of the Year
(I'd be happy.with that haha)
re the Chase shot, i just zoomed in and holly shit there are 4 people on the shoulder/paddling over it. Almost missed them its that bloody big.
And unless I'm mistaken, the paddler to the right looks like a young girl. Massive props to her!
Was following the actual winds on windytv through this. From that I would speculate;
- low hung around off the coast of Sydney much longer than forecast,
- initial winds had much more oomph on the south side, rather than the south west, meaning more an east swell than a south swell, confirmed by reports from Stu and others and local observation.
- a local, JetSki only, break between wedding cake and Maroubra that nobody ever surfs (it’s at the bottom of my street) was cooking with possibly the biggest right handers I have seen there in 30 years,
- strangely, and it has never happened before in my 30 years of living here, it was hitting there bigger than Wedding Cake,
- similarly angled spot nearby was, I understand, cooking, and guys were on it, supplying one of today’s shots, I suspect.
Hi to Dimos, who I met today taking shots at the bombie nearby.
This did not go as forecast but it was always going to be solid, but the extra day and a half hanging around Sydney and the extra oomph on the south side of the low (subject to accuracy of windytv real time showings) may explain the huge pulse on Tuesday arvo and night.
Maroubra today had pumice on the beach which went up the steps overnight. Wave action, not wind.
Sans Souci had waves topping over the promenade overnight. Check Sans Souci’s alignment with respect to Botany Bay opening.
This was an east swell for all parts Sydney and south. The biggest part of the swell was the east, not the south swell. This aligns with the unusual local observations.
I rest my case, and will defend this analysis not at all. You can have your theories, I’ve got mine. ;-)
Gotta keep in mind that while Windy looks good, it's only an animation of the models. It's not what is happening, it's what is forecast to happen.
Meaning, it can be wrong.
No way swell was east and the Port Authority live buoy data confirmed it. Got to about 140 degrees on the Northern Beaches and my local close to Deadies was shite for much of the swell.
Nah the point was average cos you surf with your tongue out .
Due to how close the low was to the coast the angle of the swell would’ve been different a few clicks further South. The further north you came the swell was more S in angle and clearly the less size.
A very non-ordinary swell event, I believe. In southern Sydney, what we experienced, was not the average, big, south swell.
Phantoms (in the above photos of Cronulla Point), is generally assumed (because it doesn't break often), to sit about 300m, ENE of a part of the Shark Island break called Surge. Those photos and what I witnessed yesterday, was an area breaking about 600m, NNE of Surge. Watching lefts pump intowards the Island, was surreal and novel. And Kudos to the foiler and his tow partner who were having a go at it!
This could be sand based (as in, have banks formed out further?...possibly), but it was interesting how this swell almost performed the opposite if what I thought it might do.
I got out for my first dip at the Point this afternoon. This was the oddest swell, I can remember. Not bad, just different. Very different.... Fluctuated between playful and hardcore even within sets. Unusually powerful and completely unpredictable
Did the Big Rock at Bondi move at all?
A good question Craig.
Hard to imagine the wave that deposited it there.
Orford Rivermouth Tassie, Wednesday.
https://imgur.com/a/IlnUXQY
Very nice.
Cheers, wasn't huge but definitely showcased what this rivermouth can actually do.
Never got the legendary Orford river mouth ,
You can see why it’s so rare , from the top photo with Maria Island blocking it off.
How is it getting in there, and how many corduroy lines in that shot?
More punters than corduroy lines unfortunately. Chasing the unicorn!!
Probably not helped by bozos posting pics of the place on swellnet the day after it was pumping so everyone knows exactly when it's breaking. I didn't know it existed til today. Can't wait to go there next NE swell with a bunch of mates!!
Why!!?? Fuckss sake! Nothings sacred anymore.
Good luck catching it on ,
Blue Moon sort of break
If you zoom in you can see how many guys already know about it
From the NE /ENE , if it’s big enough, that’s why it doesn’t break very often.
spent 10 years of my surfing life in Tassie and can vouch for the fickleness of Orford River. Surfed it 3 times !
would love to see some shots of the river mouth on that swell from ground level if anyone has any.
W/NW swell from your low hit our points this morning, and combined with a surprise straight offshore SE it was barreling, even at the softer point.
No school kids, no tourist hordes, just a few stoked locals.
Absolutely pissing down in the far north. Hoping for tomorrow afternoon W change and evening low tide to sneak round the reef.
How good! That's a rare combo.
15sec WSW swell the final magic ingredient :-)
Flip the photo of Chase's Ben Buckler bomb, looks just like big Waimea.
Cam Rewind South Bondi that Day....Its Waimea Bay....and with some Closeouts
Great read. I echo the sentiments above- that's why I stick with Swellnet.
I like sea onions more than onion rings. And that's saying something.
That bomb pic is crazy. Like Craig said, just the sheer amount of ocean behind it.
Is it possible the low was working over the top of some longer-range SE swell from the Ross Sea? I doubt many near-shore wave models would pick up such a distant swell, let alone the non-linear effects of high wind shear on an activated sea state. There's still some long period antarctic swell in the water now.
That S/SE groundswell arrived after the peak of the monster stuff Tuesday.
Banks…what banks???
"Calls around the grounds were quoting 15 foot sets at deepwater reefs with hesitant answers pushing even further north. 18 foot? 20 foot? Can you say that on the East Coast..?"
100% you can! it's an old unreliable, subjective means anyway. Straight up more reliable to guage head high, overhead, double overhead etc. Once it gets beyond triple overhead, let alone 5 x overhead it's next level. That happened this week. Yew.
Worthy comparison?
https://www.swellnet.com/news/reels/2023/05/11/watch-tim-bonython-weddin...
Did the Chinese war ship that was cruising around, drop something radioactive in the ocean ?
Gilligan, I thought the scale was half (or 1/3 if you are Hawaiian) the wave height up to 6ft.
Then you have solid 6ft 'cause there is has never been a 7ft wave.
Then you can call it either 8ft or triple overhead (even though 9ft would be triple overhead if you are the regulation 6ft)
Then you revert back to 10ft cause qaudruple overhead sounds clumsy.
But if you towed in or are a Big Wave Dave you may call a 10ft wave 20ft.
After that regardless of whether you paddled or towed you may only call it from the full wave height, rounded up to the nearest 10 ft and the scale only goes up in increments of 10ft.
For example:
3ft, 4ft, 5 ft, 6ft, solid 6ft, 8ft / triple overhead - 20 ft, 30 ft, 40ft, 50ft etc
Vince Neil reckon that would work :)
CraigThursday, 3 Apr 2025 at 6:18am
Did the Big Rock at Bondi move at all?
Anyone been Out for a Look ...Did it move ?
I say Highly likely it would have .
https://www.bondiobserver.com/blog/the-big-rock-bondi-mermaids-this-is-a...
How far south did the swell get? Eden? Tassie?
Check out @ahscotty post at 6.45 am today.
Ha my mate in Tassie sent me the same photo I thought he was having a lend of me. Flinders Island would have been firing along with the whole south coast of NSW.
And the North Coast of Tassie , ?
I've actually surfed those lefts of phantoms shark island many years ago now.
I recall looking in to south Cronulla from where i was out there, and since I have had trouble explaining to I'm sure very doubtful people why I would be that far NE of Island.
one wave I got on that 9m plus swell I was actually caught inside and had to go. it went left in behind outside surge, then when right through to behind patch.
I really hope someone one day comes forward with recorded footage of those days.
if anybody ever does, please come forward, Marcus van Riet
How's your brother, Groundswell?
Hope he's doing ok
Hey mate I'll ask him to pop on here and say gday. Cheers
NW swell off that low hitting the Wellington West Coast (Lower North Island NZ) today.
Video of That Wave floating around on FB https://www.facebook.com/reel/971664128368550
spent 10 years of my surfing life in Tassie and can vouch for the fickleness of Orford River. I've surfed it 3 times !
Would love to see some shots of the rivermouth on that swell from sea level if anyone has any.
Welcome to the anthropocentric age
"The Sydney Waverider buoy is experiencing issues due to strong currents impacting upon incoming data quality. " MHL https://mhl.nsw.gov.au/Station-SYDDOW
http://www.bom.gov.au/oceanography/forecasts/idyoc300.shtml?region=NSW&f...
Swell changed from south to SE 150 degrees 4-7m at its peak in the morning 2nd April bouy at Port Kembla, NSW.
Warm water current (25C) & moist air temps... near cyclone formation conditions.
High in the south compressed & 'cradled' the low to put an easterly spin wipping up Alfrederico
https://zoom.earth/maps/pressure/#view=-28.2,169,4z/date=2025-03-31,11:0...
Apart from the heroic Ben Buckler bomb - Can we please identify who the brave lady paddler is to the right? Wow. Bravo