Infragravity: The Waves You've Never Heard Of
It came as a surge, pushing inshore and at a rate to what I'd expect a small scale tsunami to move. Paddling against it was impossible, the rock wall only 15 metres away being a great reference point - I was losing ground despite my efforts. In the end I had to jump off the board and anchor myself, wait for the surge to stop, and then resume paddling as it retreated back out to sea about thirty seconds later.
While surfing South Steyne during the peak of last week's south swell an interesting phenomena was taking place. One that I've experienced before but not enough for me to look further into. The surge in the sea was due to the presence of 'infragravity waves', something different to the normal swell waves we usually surf. In scientific circles swell waves are called gravity waves, so infragravity refers to waves that occur within gravity waves.
We know that wind creates waves, initially tiny capillary waves, growing bigger and becoming more organised into windswell and then groundswell with increasing strength, length and longevity.
As these swell waves travel away from their source they sort themselves into wave groups - what you and I call sets - that contain individual waves of similar size and period.
If we imagine these sets travelling through the deep ocean you'll have an area of increased wave amplitude (wave height), maximised in the middle of the set and then immediately ahead and behind this a low point in amplitude.
Because the larger waves carry more momentum with them, there's a slight decrease in the water level under the larger waves and an increase under the small waves.
This in turn creates a long wave spanning the peaks and troughs between wave groups [see image below], with periods upwards of twenty five to thirty seconds though they can reach up to five minutes. These are known as infragravity waves, and they're bound (attached) to the wave groups they are travelling with.
In the open ocean, the height of infragravity waves are only in the order of centimetres but as they approach shallower water they increase in height much like swell waves increase in size just before breaking.
This effect - which is also known as 'surf beat' - is most apparent on slowly sloping beaches, and can reach up to 1 metre in height under big swells.
However, instead of breaking like swell waves, infragravity waves surge up the beach, and this is what I experienced multiple times during last Tuesday's swell event. During large swell events, storm-surges and coastal inundation beyond the normal high tide line are usually the result of infragravity waves.
My personal experience last Tuesday was the most noticeable in my surfing life and I'd put that down to the very dynamic and incredible swell event that was created directly off the coast, with wave heights rising to 7-14 metres offshore. With such a large, energetic sea state and South Steyne having the gradual sloping sea floor, the infragravity waves would have been in the order of 1 metre once inshore, surging in and out towards the beach at a rate you can't fight against, even on a board.
While infragravity waves were discovered by the late Walter Munk in the 1950's the way they seperate away from swell waves once these themselves break inshore is still not fully understood. Sometimes they reflect back out to sea and at other times on steeper shores they dissipate much quicker.
The implications of infragravity waves regarding the transportation of sand has been researched more, and observations show that they influence the temporal behaviour of rip currents, fostering the detaching of eddies which than transport sand alongshore.
Next time you're struggling to push out across that sand bar that seems to be constantly surging you inshore, have a think back to this article and maybe wait a minute or so and try and push out as the infragravity wave recedes.
Comments
thats really interesting Craig.
I think we experience a similar phenomenon here where during the heavy S to SE swells it seems for a time the whole ocean moves and shunts you northwards.
I think that is an infragravity wave running obliquely to the coast.
Yeah totally, I've experienced it as well quite a lot when surfing bigger point break or reef surf.
From the literature in regards to what they call 'edge waves'.. "but with obliquely incident waves and the breaking-induced alongshore current an asymmetric distribution in dominant propagation direction is created."
IE oblique infragravity waves propogate down the point/reef.
anyone who goes worming on the beach should be well versed in infragravity waves, even if they were unsure of the name.
I was under the impression that the bound energy is released in the surf zone as you say but energy is reflected between the shore and back of the surf zone creating a standing wave, similar to sloshing water in a bath tub back and forth. the result creates nodes and antinodes which has a big impact on sandbar development.
Yep you're correct, this also happens, there are many scenarios that can take place, including as you said standing waves, harbour seiches etc.
These long waves are particularly problematic in Harbours for moored vessels. My colleagues at MetOcean Solutions have developed a forecast product for Ports that models these lesser known waves - https://www.metocean.co.nz/long-waves
Nice Alex and great video in your link..
'Surf Beat' is a great name for a New Wave band, I reckon.
I'll get my jacket.
That ship looked like it was jiggling to a catchy surf beat.
Fascinating stuff Craig, on a subject I've never heard even whispers about until now. It's interesting how the infragravity waves seem to peak when the regular sets ease off into a lull, then dip when the next set reaches its peak. The universe is an endlessly fascinating place.
Interesting phenomenon. From an audio engineers perspective it makes sense that a number of set waves could have an underlying fundamental frequency. Each set wave is briefly in alignment/ perfect phase leading to a large output of energy.
Craig, i also experienced this paddeling out at south styene. same time..
The only other time iv experienced this was up the coast while on a 'trip' and ended up saving 3 poms. within a seconds the flash rip was gone and was back to getting barred.
crazy experience.
Yeah how insane was it. I’ve had a few messages in Instagram from others at other breaks experiencing the same thing. Oh and just when the swell was starting to kick proper Tim, Max’s dad from Queensy was out and said the water started moving and swirling weirdly. This would of been the same phenomenon.
Mean while Max caught the biggest barrel iv ever seen...
Quantum
Can confirm both of the above haha
Soo... tell us, anyone grab photos of it?
Cant confirm that unfortunately, it was earlier in the day around 12. Not so many cameras out then maybe
Tony Butt in his excellent book Surf Science talks about infragravity waves. Wonder what effect they would have on Greg Webbers proposed V wall
This looks like one of those waves close to the bommie that were coming through completely sideways, crazy!
Another good article.
so,is the bounce off a rock wall or point an infragravity wave or just a bounce of normal swell?
Nah, that’s just the swell waves bouncing and reflecting as you’ve said.
So fascinating. Could I have some help with this aspect: "Because the larger waves carry more momentum with them, there's a slight decrease in the water level under the larger waves and an increase under the small waves". Momentum is the mass and velocity of an object (the gravity waves, in this case). How does the greater mass and velocity of the larger waves necessarily lead to the slight decrease in water level and the opposite for small waves?
Don't quote me on this but I believer it's because these larger waves displace more water, hence decreasing the ocean level more as a whole.
Larger waves have more momentum than smaller waves travelling at the same speed simply because they have a greater mass. I'm thinking that because water molecules cohere quite strongly, larger waves actually carry water forward leaving a trough in the infra-gravity wave behind them ......... but I could be wrong.
Hi Craig,
What's the effect called when you're surfing in a (relatively) small bay and the water starts sucking out of the bay ahead of a set (I'm thinking Blowholes in Albany here)?
Noticed this a few times. One recently a 6ft day a mate and i were walking in waist deep water with my daughter at the cowrie hole and the ocean between sets all of a sudden flooded in knocking my daughter off her feet.
Had something out an island off tge central coast. If you get caught inside near the island cave cliff you wait till it all builds up and rushes back out. But that wouldnt be infragravity. I guess its just delayed backwash trapped between the cliffs and a bombie
Not sure if this is the same phenomena but year"s ago i noticed that the sea level falls noticeably well before a set arrives. On tiny days if you are standing on the sand the water might drop about 6 inches. On bigger days you need a reference point such as a visible reef bottom or water colour change due to sun reaching the bottom more easily to pick this up.
What this does is give you advance warning of a set approaching often well before you see it approach. It is not really a current of water so much as a mysterious water level drop. This can be very useful if you are sitting close in and need to move out ready for a set and can give you an edge on the crowd on some days.
Gave away my secret there.... oh well.... a few less set waves coming my way but all the swellnet forumites can send me $10 to compensate.
I,ve been relying on this my entire surfing life . Rarely caught inside at Heavy off shore reef , breaks often exposed to sneaker sets .
Without visual indicators of water depth , boils , eddies and actually being pushed towards the shoreline off your markers can be tell tales of impending sets . often minutes in advance and sometimes well before " indicators " breaking further down the coast show and alert the pack .
Launching tinnies and Jetskis off the beach inside protected reefs , this sort of knowledge can be do or die for your beloved machines .
My understanding was that sea level is elevated where you have the wave group (set). The longwaves form in-between the sets to maintain isostatic equilibrium. Because wave height is the main factor for the depth which waves break, the sets slow down near shore and cut the longwaves loose, so the longwaves should arrive before the set they were originally behind in a normal beach scenario. One of the cool things we were taught at uni was that the long waves reflect if they come straight in but if they hit the shore at an angle they can refract and reflect so sharply as they hit the shore that they can actually propagate up the beach kink of like a slinky going down stairs. The nodes of the longwave pattern as they refract/reflect up the beach then helps form the bar and rip pattern on some beaches. I think this might be more significant on super protected beaches where you see prominent rhythmic burms at the shoreline, I noticed this at Bundeena a while back, (I am speculating a bit perhaps someone that knows better can jump in...)
I thought similar Jez, but no it's counter intuitive and lowest where the set is. It's 180 degrees out of phase with the sets.
Those other points are correct though and it should be noted that when impacting the shoreline the infragravity wave takes a phase shift away from 180 degrees, slightly lagging the incoming set. So it usually follows just behind the set.
Thanks Craig, I think I explained myself poorly. I know that the peak of the longwave is in between the sets but my understanding was that the longwaves exist to maintain isostatic equilibrium between the sets because the sets 'would have' a relatively raised sea level relative to the area between the set if not for the presence of the longwave. Is that correct?
Ah yes, not sure on that but you're thinking seems to be correct. There's a great paper here if you've got the time.. FIELD OBSERVATIONS OF INFRAGRAVITY WAVE RESPONSE TO VARIABLE SEA-SWELL WAVE FORCING
Also here's a great example of infragravity waves surfing up the beach, unstoppable.
No need to watch the rest of the video, just from 40s.
I always just assumed and referred to it as a 'storm surge', set waves pushing in extra water, thanks Craig for giving it an official title.
Another interesting one is the displacement of water caused by cargo/tankers (this could also be similar to a low pressure event passing through the ocean). Plenty of interesting youtube that shows water levels being lowered as ships pass prior to the wake arriving.
Thanks UL, I guess the main difference is that these infra-gravity waves occur even without large stormy swells, it's just that they're more significant during active swell events.
One classic example that we see during the Pipeline CT events during large swells is the infragravity waves surging up the sand and taking out the spectators and cameras, destroying all their equipment with it.
Great story Craig...(It's those little waves that bowl you over!)
Bodybasherz can't escape this world as we can't paddle nor can tbb swim well.
Point breaks!
Standing in 3ft water the first set wave rips by with a deeper trailing wave.
2nd wave breaks in 4ft of water with trailing wave sweeping more mass & speed.
3rd set wave swamps 5 ft of water trailing another low size wave of massive force.
4th set trailing wave skips a flood over whole bank washing all inside down the point.
So awesome that only those wide of the line-up escape it.
Note skip waves 3,4,5 feed off their host & may even consume their waning host.
Trail waves may be small but each build in volume to travel faster & further
This happens more often on bays & points where such momentum can carry.
Note: Set waves mostly back off to last whereas each skip wave gains power to last.
tbb is seldom washed off the bank by a larger wave but Craig's waves run like rivers.
These all encompassing waves sweep one out to sea or be flooded 200m ashore.
A more telling gauge of the oceans sustained power for sure.
As said here...same waves again consume the set waves heading back out.
This is when swimmers get dragged of the Back Break & caught in undertows.
When bodysurfing for long sessions you must time them our exhaust yourself.
Note: Craig's waves carry far greater volume & force hidden beneath.
Similar to still water runs deep saying. Even dams have massive wind Current.
Body basherz utilize this wave force to porpoise ashore beneath the rip.
We also neutralize this equal wave energy for no stroke/kick takeoffs!
With experience this wave force is harnessed for reverse or forward Barrel Rolls.
Bodysurfers source this force to marry rotation manoeuvres otherwise arduous.
Meaning a bodysurfer must mould shape to harness skip waves hidden power.
Be that running beneath or combing over, one's body atunes to nature of the wave.
By same nature a Bodysurfer gets ragdolled as 2m nearby a learner sits & smiles.
Craig & readers might wanna explore this alternate modern twist with similar effect...
Credit: NSP Surfboards - Wave Pools in 2019
[What you never read or see in the videos]
https://www.nspsurfboards.com/surf-wave-pools-in-2019/
"Quote is fully credited to NSP surfboards from Wave pools 2019 review."
*Current
"You don't really see this in the videos,but a wave pool running at full capacity will oscillate.Once engineers managed to generate sizeable waves they quickly discovered that their biggest hurdle in creating consecutive waves, is the current these waves generate.Several visitors report their initial surprise at just (how much effort it takes to stay at the right spot)and you intuitively look for something to hold onto.
To counter this,existing wave pools are being retrofitted with drainage rosters and newer installations are designed with complex software that helps dissipation of the kinetic wave energy!"
tbb's Rip Roaring Bonus...
"The Wave Pool you never heard of (Shh!)...tbb is caught in the Rip Zone!"
1936 Portobello (X Large) Heated Wave Pool also harboured a massive current.
{ Contribution from Mr A. Lightbody D.I.S.R.M }
"Due to the dimension of the pool (100m x 50m) and heavy bating loads and in order to make the waves reach the shallow end of the pool the waves had to be very high at the deep end (3ft+) resulting in backwash from the shelving beach making a millrace type of current returning down the middle of the pool.This created a dangerous situation where non swimmers could and were washed out of their depths.
Safety Ropes had to be provided across the pool mid-way and during wave periods,pool attendants were kept busy rescuing the bathers swept off their feet." (Off the record...Sean Connery was one of the said Life Guards)
https://www.bathsandwashhouses.co.uk/archive/your-local-buildings/edinbu...
Read between the lines! Portobello pushed out a 3ft shapely right & left for a full 100m!
Other photos show waves slamming the shallow end. Yes! Pool allowed Surfboards!
Isnt it just the set waves breaking turning wave energy into a volume of water trapped in the surf zone. Which forms the peak infragravity wave between sets and which then escapes via flash rips etc
Nah different phenomena. Proven by doing experiments with offshore bars, and the intra-gravity waves travelling onwards to shore.
Ha ha still can't work it out at the fundamental level. Either it is more complex than I am allowing for or I am missing something. Off to Professor Google for a while!
Yeah def more complex, check this image for how complex it can get if you want to go deep..
Full paper here:
Infragravity Wave Processes - Recent Experience in New Zealand and Australia
Thanks Craig. Managed to fit in some decent research on ordinary gravity waves this am.
Thanks, great article.
Now I'll be able to get it right next time i'm telling my daughters the water is on its way to fill our moat! Always wondered why the sets ended in disappointment and didn't find their way up the beach.
Thinking back, it seems that on small days with frequent sets the longer 5 minute period would be on the money.
My apology Craig! I do now understand what you described to be an actual thing!
Just going by what you experienced when paddling + the science + Vids.
When I think hard it's not always set wash that drives me back out drags me out.
I do now understand what you are describing more so by feel, than science papers.
I'm guessing the surf beat plays it's own beat, dancing between the set waves.
So the gravitational wave can interweave before,during,after or between set waves.
I'm also guessing coastline & depth dictate how these waves may or not sequence.
One study paper insists the lull period needs better focus because of said waves.
I also often recall many beach breaks that have exhibited this strong force as well.
Usually these waves sweep arrears on Point sets but advance the lull on Beachies.
Also exaggerated on banks with drop off gutters pinning surfers with little swell.
At these times a bodysurfer feels like giving in as it's impossible to swim against.
I feel these as massive deep walls that push inbound stronger than tides that rip out.
Again I don't feel the wave face as such more so the considerable moving force.
Many ask if one can surf a Gravitational Wave?
https://cdn3.theinertia.com/wp-content/uploads/2016/02/Shaka-Einstein.png
Oops! Try this Board...
https://www.facebook.com/9NewsGoldCoast/videos/a-byron-bay-surfer-is-mak...
Thanks again Craig for sorting out our wild blue yonder!
tbb should have no problem bashin' the gravity outta this big bully wavelength!
Hey Craig, love these articles. I didn't know the name of this wave type at the time but managed to capture some video of it in the harbour last week:
The funnel shape of the coastline mixed with the harbour wall and the surge of the water creates a weird little wave every minute or so. There were no shorter period waves observable at this spot. Water quality looked a little dubious so I passed up a novelty surf.
Fantastic! Well captured.
That's the best example I've seen Thingo, great capture and 10/10. This also proves that the infra-gravity waves aren't made from breaking surf. A real pure example. Thanks for sharing.
Wonder how often they’re confused for small tsunamis?
I witnessed a series of small tsumamis after the 7.8 Kaikoura earthquake here a couple of years back. They were more like a rapid rise in the water level rather than a wave I could identify. Somewhere in the area of 200-300mm. high. This was nine hours after the earthquake, so I guess the ocean was sloshing round like a bath-tub in Cook Strait.
Heard a couple of local stories on the Tweed Coast about older crew 'surfing up the creek' on longboards at Mooball many decades ago. It's now obvious what kind of waves they were riding.
Whenever I'm fishing there, I occasionally see infragravity waves push a reasonable distance up the creek, even on small swell days - and that's with the mouth of the creek sometimes no more than a metre or so deep.
I’ve heard those stories too, always thought they were tall tails until I was working at a farm property backing onto the creek way up near the Tweed gallery south of murbah during Oma and witnessed it first hand. It was relatively still on the creek but then a 1ft wave came cruising up and sloshed its way inland. Too pronounced to be tidal. Was a spooky sight and sound
Thanks Craig, came across a nest of these massive sweeping sleepers from Oregon.
Seems the Locals get off playing chicken with them...
*Everyone laughs off big wave then a 1 ft high wave @ 40km/hr comes at them. RUN.
*Love the jet roar of this one...Like a concrete mixer it is!
*This silent one really paints a vivid picture...poetry in motion.
*Final one! What can you say! That's an awesome display of power (hit refresh)
This clip puts out...slow to massive rush...Loamy Left in the soup, then Rogue right.
Gravity waves in the NW sky vid !
https://www.abc.net.au/news/2019-10-23/satellite-captures-rare-atmospher...
The last few days have been an excellent study in infragravity waves in Far Northern NSW. Surfing and watching a couple of the region's headland/points, it's been incredible to observe these waves - sometimes between sets - slowly move up the coast, usually creating half a metre standing waves that make it impossible to surf through, or paddle against. And the acceleration in sweep has been incredible.
Similar experience here in Sydney and very noticeable swimming back into Shelly Beach with the camera multiple times.
I'd get about halfway in and watching the rocks to my side I'd notice that I'd stalled my movement towards the beach and even started heading back out to sea when kicking constantly (not a normal rip action).
I knew this was the infragravity wave sucking out and after 30-60s or so it was going to be pushed back in... and boom like that, the pull on me stopped and reversed, surging back into the beach and putting me onshore within seconds, flying past the rocks.
I definitely felt the same thing both paddling out and coming in at Shelly on Sunday arvo, me and a mate were joking the current was pushing whichever way we weren't going.
Mental eh, now you're aware of it, you'll notice it much more often.
I'm pretty sure the humble pippi is in tune with this phenomena. Have seen them take advantage of the ebb standing wave which gives them a little extra time to extrude feet, step to the left - or right - and march sidewards up the beach. They can swim -float with style - but also march to areas with higher phytoplankton density. Could be wrong.
Related to earthquake NZ recently?
No.
Pretty sure I came across this phenomenon this morning, even with the drop in swell. Local permanent rip started surging backwards for a couple of minutes!
Those getting in and amongst this East Coast event and also on the Western Australian coast, there'll be strong infra-gravity wave action so keep an eye and feel of it. And please, feel free to document it below.
The infragravity surges at Spectator Rock during the mid-high tide through the peak of this cyclone swell event today were insane. Literally taking you off your feet, even dragging backwards on the sand with feet planted. To punch out without losing too much ground you had to time it when it subsided and started retreating, but also not when a set was coming.
The most current I've ever experienced on a point break.
Great read Craig , this is laceration on lembongan , it was only 3-4 ft then 12 rogue waves came flying through , that’s Dylan Longbottom and his family swinging from the pontoon . It did quite a bit of damage to shops on the beachfront , all over in minutes and back to normal swell , bizarre. https://www.facebook.com/1404102748/posts/10204553906993358/?d=n
Wow SF, maybe caused by subsea landslide/collapse?
No idea , freaked a lot of people out, just out of nowhere , I’ve seen the swell increase from 2 -8 ft over a few hours but this was just BANG
Any reports from Bali at around same time?
Sorry SS for not replying sooner , I didn’t really seek any reports or hear anything but the date is on the photo so it would be possible to check , I think the whole episode only lasted about 30 minutes maybe , lots of tidal surges with it , I wasn’t surfing but looked over and thought holy shit the swell jumped quickly. Mate told me yeah it was Dylan out there a few days later.
Same, but different.
Incredible!
Great footage of infragravity activity on the Gold Coast yesterday..
Did all that beer come out of that "permanent" storage that the doors were ripped off, not the container?
How many years before that surf club gets abandoned?
It's on the beach FFS.
Yep out of the "permanent " storage haha.
Recorded some impressive infragravity waves myself yesterday morning, just inside the mouth of Cudgera Creek at Hastings Point (Tweed Coast, NSW).
Video below was taken at 10:08am, around half an hour after the predicted high tide of 1.62m at 9:36am. At the time, the nearest tide gauge (Tweed) was recording about 0.28m positive residual.
Coupla notes on the location: it's extremely rare to see any kind of wave activity push past the narrow point of the spit, around the corner, and up into Cudgera Creek. However during these kinds of high swell/storm surge events (and especially during the high tide), water flows over the sand spit, and infragravity waves are able to propagate more efficiently through the creek thanks to deeper water at the mouth. In the image below I've marked the usual high and low tides, and then the storm surge tide mark - which to be honest is only held back by vegetation... a couple of these weather events in quick succession would erode the dunes back further and create a broader swash zone.
Anyway, in this video you can see the leading edge of the infragravity wave pushing through on the far southern bank of the creek (on the bend) and over the sand bar before pushing through the channel, and then breaking as a knee high wave on the western shore of the creek (to reiterate.. this is very uncommon!).
That then reflects off the shore as the bulk of the infragravity wave starts to push through the creek. See the large tree branch gather speed (middle of the creek) and then as I pan to the north, check the swimmer who entered the water directly in front of me twenty seconds prior, who also gets whisked up the creek (he was fine). Lots of water surging up into the grassy park too.
The video lasts 1:30 but the IG wave persisted for a while longer, maybe another minute or so.
No jumping off the bridge today!
There it is!
Insane infragravity wave action today..
Craig, Ben,
Fascinating story. Never thought much about the science behind the different surges and outlier waves like that that we see.
Living onboard my boat at the Wharf Marina behind Hogs Breath Restaurant at Moololaba, 2km from the protected rivermouth entrance, and where the river turns a full 180° between there and here, I normally sit quietly at my marina berth. Always know when a big swell starts though, as out of nowhere the boat suddenly starts surging slowly back and forth on the mooring lines, and occasionally you wander out and all of the boats are getting pushed around a bit on the dock. Plus you can hear the walkways creaking and moving around and your mooring lines getting tweaked and creaking as they tighten then release again on the vessel and dock mooring cleats. It would be interesting to time and monitor the pattern actually, as it isn't consistent throughout the day, and can come in surges, which I always just put down to bigger sets, without really thinking about it.
Wondering too, how much those surges / waves might temporarily add or subtract from the tidal flows moving up and down the rivers at the time.
Also, your diagram shows just one swell. Was wondering about similar in mid ocean - even though not as noticable - but where you can have a huge N groundswell, a huge S groundswell, a decent NE windswell, a SE windswell, and then localised windchops, all on top of one another. Can get pretty messy out there.
Jody Perry
Infragravity waves from 15s onwards, surging up Soquel Creek, in California.
And another video..
A great example of an infragravity surge..
And more from Brazil on the weekend..
Thanx Craig...request for swellnet intel on WOTD~~~~/(C`[ meteo-tsunamis )
This Brazil event and many earlier similar past events are being heralded as Meteotsunamis
https://www.miros-group.com/leveraging-digital-sea-state-data-in-real-ti...).
Group of many waves (Can be 2mins) >15mins -5 hours procession are labelled as one Meteotsunami
These waves can rebound & restoke several times over to rag doll the town...like enough already!
Gonna ask for Craig's Guidance on the Weather Side...to MeteoTsunamis
tbb can pull apart which exact Hot Spots and Why mankind plays a leading role.
Pretty sure any Surfer or School Grom could crack this meteoric mystery in even less time.
The answer is Lightning Fast E Bay ports are stirring up shit storms by lighting up the skies!
E bay = Shitstorm = comes back as meteotsunami = Climate Change #1 Exhausted Hot Spots
Tech revolution is heating up well faster than 100 x 1,000 Industrial revolutions.
Mostly coz this overlays with Pop / E bay / Shipping / Lightning / Estuary / Erosion / Seachange
We can rule out most Old World wide open Deep Shipping Bays...they're not involved in this caper!
But continue with Busy dredged Shipping Lanes into newer Equatorial Current exhausted Ports
Basically talking about continually silted dredged Equatorial shipping lanes fast tracking estuaries.
More common where Humans force feed their Pet Ocean into these lightning speed shallow E Bays.
The increase in strikes correlates with Water > Pop > Ebay > Ports > Seachange Storms...on & on!
Erosion Surf Port shipping cities fuel Lightning Storms that self generate more meteotsumami strikes!
Like heat ions from Slot Cars > Lighting charged shallow Port channels light up Surf City Tower > Bang!
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EA002926
Cutting of Equatorial Canals "Depth" Currents port where currents freely take them.
Simply click yer mouse to ramp Seachange speed > More clicks more Turbulence > Storms > Erosion.
Not rocket science speed dialing #1 Life Cycles into E bay Blenders...Can't breathe = Shit Storm.
Recap : Not Biggest busy Wide open Ports nor traditional desolate hottest lightning Hot Spots.
Were talking about E bay magnet Sea change super charging 80% life-giving Esturarine Lifecycles.
World Clicks & demands next day thingy racing closer to kill the goose that lays the golden egg.
Mowing down Islands > Coastlines > Bays & 99% critters to pile higher to burst the clouds..Kaboom!
Yes! I got the thingy in World biggest Box in record time to regurgitate it on Tik Tok...around again...
All fighting to drink the last drop from the shiniest polluted wishing well...more want the same things.
tbb will start tracking from SEQ end of the Meteotsunami Wave Train to get things rollin'
Please don't think this as dull...tbb promises to recycle the whole deal just from his local.
Mostly coz tbb knows of anomalies from 10 years back but can only now group them together.
Other than that...this would be real tricky to track the real reason.
Start (Intro)
Huey serves up frothies for the crew but then hammers down hard on the punch...Strewth!
Better stand back ...bit further...up in the arms of yer Saltwater Godz!"
Huey coughs up Wave after Wave...'Can't stop hiccuping!'
Evening in 1914 @ Straddie the Liberty (small boat/dingy) surfed over of 40ft wave...
Followed by another & another about 30ft high & 100 yards apart..kept comin' for 4 hours it did.
2 other boats smashed onto the beach at Cape Moreton but the Liberty rode it out & surfed ashore.
https://www.swellnet.com/news/swellnet-dispatch/2019/07/28/queensland-ts...
https://trove.nla.gov.au/newspaper/article/97988720?searchTerm=tidal%20w...
That sounds like a far fetched story but 100 years on...Qld Govt record similar in same patch & at night!
Sat Midnite 3/4 Dec 2016 Fast moving East Coast Thunderstorm...
The pressure step ranged from 5.5hPa to 9.9hPa over 18-99mins...
Ramping a SEQ meteotsunami in the form of 10-15 waves with one steeping twice the height of others
Just as the fisherman recorded a century earlier ...series of smaller waves but kept up for 10 hours.
This Timed or was fuelled by Sun' dawn Southport Seaway 04:13 am Lower tide of [0.25m]
Please note the low tide level for neighbouring tide levels...
This 0.46m meteotsunami hit GC Broadwater & Brisbane River at 10.6 m/s
Most waves were recorded towards the very low tide to limit any early Dawn damage...
Route 1 GC Broadwater Wave Break Island/s were choked in sand...Meteotsunami was detoured north.
https://www.goldcoastbulletin.com.au/lifestyle/beaches-and-fishing/gold-...
Route 2 (Dec) Port of Brisbane was deeply dredged to welcome biggest ever ship...
Never been a more Perfect Storm welcome mat to funnel and speed a Meteotsunami far up river.
https://www.dredgingtoday.com/2016/12/01/port-of-brisbane-able-to-handle...
Forging up Brisbane River & slowing to 5.8m/s at a height of 0.13m as it split at Bremer River Ipswich.
err...that's a 40km ride from mouth of river + 90km ride from mouth up to the Weir = 130km ride.
Perfect longest Wave Pool ride in Oz...only all boardriders were asleep...the perfect bummer!
Type in [ Meteotsunami in Queensland Fact Sheet] or
file:///C:/Users/Owner/Downloads/meteotsunami-fact-sheet%20(13).pdf
or if Qld Govt lock you out...
type in [ 2019 Australasian Coast and Ports conference paper by Daryl Metters ]
https://search.informit.org/doi/10.3316/informit.801428431137365
hfile:///C:/Users/Owner/Downloads/2016queenslandtidetables%20(2).pdfttps://search.informit.org/doi/10.3316/informit.801428431137365
From here we head South to neighbouring NSW...Please to recap the esturarine difference over time...
100 years ago many choked out bars would've back washed dunes to stoke larger meteotsunamis.
Many examples of exactly that...
But less effect on inshore estuaries & little to no up river range.
Today...Brisbane + Tweed Rivers constantly dredge to both invite & funnel anomalies to up river weirs!
Basically wherever you look > It's recently dredged to invite & speed the Weather.
No coincidence that Brisbane recorded theirs as exact point in time of max dredged point in time!
Same as Tweed...
Extra upon this...please check Tweed River Bray Park Weir top overs...
Tweed council lock in and top up wall for 26 predicted tidal / Flood breaches in 3 years or 9 per year!
Tweed record 2 Metotsunamis or tidal wave anomalies breaching Bray Park Weir 35km up Tweed River
21/22 Aug 2017 Top over ( No drinking water supply for 2 days + $400,000 desal )
[factcheck] 2nd Feb - 31st Aug 2017 (Most Dredging [216,605m3] since 2003 (Perfect timing)
2017 Massive Pump totals 58k / 50k / 39k / 69k > July Bam! Surprise! Surprise! Tidal Wave tops weir.
Lowest tide [-0:01m] + Record Dredging fast tracks Esturarine Ecosystem to fuel anomaly.
A coincidence that lower tides + record dredging fuel anomaly tidal waves topping both weirs? C'mon!
Wanna surf again...tbb is on a hat-trick...same rain dance...same top over...shall we!
Jul 2019 also backed up to keep fast clear channel [151.650m3] next highest pre 9 yrs / post 3 yrs.
The next breach comes after *next highest sand pump kicker since last 2017 top over (Lets go again!)
2020 Mass Pump totals *50k / 26k / 38k / 27k > May Bam! Surprise! Surprise! Tidal Wave tops weir.
Another low [0:30m] & away we go > Another tidal wave tops the weir by following the ramp formula.
25 May 2020 ( 320mm Wave washes 15ML of ocean over Bray Weir fresh water supply ) = Same!
tbb scores a Hat Trick or unravelling 3 local anomalies in one swellnet posting...how about that! Bingo!
Recall above...Grom could solve all #1 Local tidal anomalies...even tbb outdid himself...stoked!
Should tbb front the next conference on this mash up! Would ya want to...Hmm!
Reckon tbb 'd get booted out within 5 minutes! See ya mate...all know this White Collar rorting!
Can lock in the max dredged pattern...to fuel another top over 'Anomaly'...100% Guaranteed!
How the fuck is that an anomaly to throttle the estuary to fast track it's lifestyle to cough up the Ocean?
That's 3 examples of exact same record dredged / pumped / low tided river mouths process...
Each end with tidal wave breaching well up river weirs & no other anomalies but those three! Huh!
* Highest ever Mankind ramping of neighbouring Estuaries results in only recorded 3 anomaly tides!
Please...Ask how the fuck can operators of these Ports claim exhausting an Estuary as an Anomaly?
https://www.tweed.nsw.gov.au/council/news-updates/latest-news/media-rele...
tbb previously assumed these Tsunamis may have been triggered by epic Moreton/Byron Canyon Slips.
Yet another biblical proportioned Tsunami waiting to happen that also feeds East Coast sand stores!
Now tbb is trying to sort that by grouping these local meteotsunamis that push up to the weirs.
Crew can decide if that better fits...mind you, this is exclusive to swellnet...so cut tbb some slack!
Pioneers silted up all bars & forced them to surf raft Goldie Breaks.
Early gen surfers were more interactive with sounding out iconic wave break forecasts & Big Wet.
Rafters would tie up on reverse tides...the go again...
However the earlier Rivers were too clogged to surf any upriver meteotsunamis.
Progressive Equatorial Esturarine Shipping > Farming had silted estuaries to rise tides to eat beaches,.
Needing mega dredging to now funnel meteotsunamis faster further up river to eat the farmer's soil
What can be done...
Council could withhold drawing water for hours leading to predicted " Similar Storms"
Pump dam full of fresh water to push back against evil Meteotsunami to "Naturally" flood the town.
Quite obviously any enquiry establishes that's Not the Mayor's Fault...but the evil intruder!
Where as a Rain Bomb, your Mayor pulls Dam lever to flood the town in a more caring fashion!
That enquiry rules that the Mayor never pulled any lever...he pressed a button...& will sue the media!
22nd June 2022 Tweed Council Voted to raise the Weir Wall Height....
https://www.echo.net.au/2020/06/council-votes-to-build-saltwater-barrier...
So it's unlikely any near future Meteotsunami will be outed as Pubic spill overs as shared here!
Councils will still record them ...but no public or farmer / fisher will be informed without request.
Bit like daily Covid wastewater reports...yeah / nah...that's secret men's business...censored!
So yeah...tbb busting open the Port Rort is an anomaly...sure let's stoke up another Meteotsunami.
This comes as no surprise as just 2 clever Indigenous can change a complete season in a few hours!
Believe wot yer like folks...tbb is claiming outright that Ports are leaders in fuelling Climate Change.
Check the top 300 metotsunami Hot Spots all the same great race as these local tidal Anomalies!
Welcome any to better explain the above coincidences more decisively...luv to see that anomaly!
PS : tbb did try to locate weather charts for these 2 Tweed events but BOM declare such intel is taboo!
Can honestly 'relate' one from memory to a Storm mop up...not so sure on the other.
Sorry can't really 'swear' to a local weather anomaly preceding either sea anomalies...luv to know!
Some Tweed media link archives are now behind pay walls...
Possibly check on outdoor news around said dates in local archives...Happy to share / solve Anomalies!
Sorry TBB, missed the post above, looks like what NOAA is calling a Meteotsunami is likely infragravity waves. Have to read a little more on their classification.
Here's more footage from overnight.
More infragravity surges, this one from one of the largest swells in years across the Marshall Islands.
Has to be 1-1.5m!
Fark that was radical. You would be freaking out about what was coming next .
Like a sinking ship.
Wonder how Martin Daly's vege garden fared?
Incredible footy.
More info- https://www.rnz.co.nz/international/pacific-news/507233/freak-waves-caus...
Agh, thanks suchas!
Didn't read through all the comments, so apologies if already covered, but infragravity waves are incredibly useful for rocking off. Do it when the IG wave hits, or end up on Lennox Rocks Instagram dry docked.
Totally IB, can fully just fill up, up and up allowing a real nice easy entry, but as you say, get out there before it starts receding!