Question for Ben, Craig or anyone with meteorology/physics/fluid dynamics background: is there a defined sea-state inside the eye of a cyclone? Further, is it LSD style weird?
Reading up on a doomed ship I mentioned here, I came across a remarkable extract. I'll set the scene.
March 1912, off the NW coast of WA. Steamers do the circuit from Fremantle to Broome, Wyndham and back with a mix of materials going north, and produce going back - as well as many increasingly wealthy passengers. Getting into some of the ports is still a very rudimentary affair, and ships need shallow, flat bottoms. It's at this point on the 19th that the Balla Balla cyclone began to ramp up with much damage and many lost ships resulting.
Further up the coast at Port Hedland the next day, two ships prepare to leave and get over the sandbar. One, the Koombana, gets out and spends some (but tragically not enough) time filling ballast tanks before setting off NW toward Broome and into oblivion; the other, Bullarra, follows for a while then turns SW to head down the coast back to Fremantle. In a life or death struggle, Bullarra manages to sail right into the eye of the cyclone and uses every trick in the book to stay afloat. She also manages to sail right into the eye of the cyclone.
It's here that Lewis Carroll takes over the physics engine. I will quote from "Koombana Days", ch10, p161-2:
"At 2 p.m., with the glass reading 27.80, the force of the wind
ceased, and the vessel was in the centre of the storm, where light
variable breezes were encountered. The seas, however, were high and
dangerous, and instead of rushing down on the gallant ship from one
quarter they hurled themselves in conical shape from all directions,
“flopping up and down.” "
Have any of you experienced a swell to do this? Instead of lines of swell, for the waves to be conical, come from all directions, and flop up and down? Anyone sailed through the eye of a cyclone?
Wow, never really thought about such a scenario.
I suppose it'll depend on the former path of the cyclone relative to its current position. Could be a number of scenarios - for example there could be underlying groundswell from one direction, generated over the previous days, and a recently-generated short period swell from the opposite (or oblique) direction, which could give rise to the description above.
Either way, if you're in a boat, I don't think you wanna be anywhere near a cyclone!
Yeah, that's a super interesting concept. Hopefully there's someone out there with the relevant scientific expertise to shed some light on things.
My area of expertise is Carpentry, but in the time honoured tradition of Internet forum discourse I'll nonetheless forge ahead with an entirely uneducated opinion of my own...
In a perfect scenario, with no underlying swell and a completely stationary cyclone then there should be no swell whatsoever in the eye of the storm as all the swell is radiating outwards.
That's all I have for the moment.
Was in Cyclone Winifred. Didn't see a sea state like that, but did see swell moving away, yes going from beach towards the horizon, but this was due to catabatic(?) wind after the eye passed over.
Good topic VJ......
I was on board a Jack up rig in the Gulf of Thailand in 2011 and we sat through a cyclone that tracked almost directly over our position. We had about 72 hours to de-mobilize most of the crew/ workers and sea fasten all deck gear.
Within the last 24 hours there was a distinct jump in the swell from the S.E, so we jacked the unit higher to an air gap of about 10 meters [ hull bottom from sea surface] and waited it out.....The sea state during the final 4 hours of approach was crazy with a distinctive groundswell passing 3 or 4 meters below of hull.
At about 2300 hrs that night the anemometer peaked at 85 knots and the rig was grinding and creaking due to windage and wave action.
Within an hour of the wind peak, it suddenly eased to a mere puff and the erratic sea state disappeared to reveal an oily surface with the ground swell dropping off by the minute.....It was pretty eerie really as we could walk around the deck to survey the damage......At this point we were in the eye of the cyclone.
20 minutes later, the tell tale sign of the wind rapidly picking up from the opposite direction with the return of the localized crazy sea state and the wind peaked at around 70 knots, slowly decreasing until about 0400 the next morning......By 0600 the sea was glassy clean with a 1 meter dying swell.
You might recall how the Onslow Harbour Master refused entry for 2 trawlers running from Cyclone Bobby in 1995, sending them back out to sea. Sadly ending in the loss of the two vessels and the loss of 7 lives.
The curriculum for Masters qualifications focuses very heavily on meteorology and cyclone navigational strategies, obviously aided with all the electronics to guide you through...
The poor old crew on the Koombana and other vessels of the time only had the trusty barometer and compass plus a good dose of experience to get them through...
Excellent responses - this is what I'd hoped for! I welcome theories from carpenters to QC's to actual oceanographers! Megzee and Dave, you guys look to have actually been in the eye of the storms, that is pretty epic in itself. I never have, though I've experienced some pretty decent cold fronts, and Coral Sea lows when I was a little kid in QLD (used to beg to sleep outside on the verandah of the flat so I could experience them!)
OK my theory - from a building surveyor and a history grad - the cyclone is grinding along and features an atmospheric low - and a change in the sea level. Maybe sea level's higher outside the cyclone as winds push everything away, and maybe it's lower inside the centre? The sea floor cops a great change in height with the storm, and a 'bouncing effect' occurs where the cyclone travels, creating these weird conical waves if the cyclone stalls in an area suddenly?
Megzee: the old timers used to look for strong building easterly wind and falling barometer on that coast to ID a potential cyclone within the season it seems.
What's the chance the Balla Balla cyclone made standing waves?
Wow Megzee, crazy story, and VJ, inverse barometer effect, def higher sea surface elevation in the centre. But what this looks like as it moves, interesting.
Not related at all but this image by Greg Cole is something to wonder at. Looks like a wave surging off the reef and then into deeper water making that weird depression.
View this post on Instagram
And as Ben said it depends on where the cyclone has been and it's previous movement etc regarding exisiting sea state when winds go calm.
It's great to theorise and imagine eh! Going through various East Coast Lows, coastal troughs etc and seeing the weather/wind go calm and switch it gives you an idea on the change in local weather around you, but sea state is another kettle of fish.
VJ, your theory holds a lot of water- Pun intended, but you are very close to the mark. A rapidly falling barometer on any coast or offshore location is a tell tale, things are turning for the worst. The lower the barometric pressure near the center, the closer the gradients, the more intense.
The cyclone I sat through must have had an eye possibly 10 miles across as we were only in the calm eye for 20 to 30 minutes as it continued on it's path.
I'm a Marine Surveyor [ Hull & Machinery ] and got into rig moving several years ago. All Warranty providers will require Met/Ocean data based on 100 year or 50 year historical data for any location approval.
From my experience, Typhoons or Cyclones in the South China Sea, Bay of Bengal, or Gulf of Thailand gather strength and tend to move more rapidly than their brothers in the Coral Sea, Gulf region or the North West. These Southern Hemisphere buggers can sit for weeks and not make up their mind.
Story has it Cyclones were always named after women because they were full of hot air, unpredictable and downright destructive, but grandad had some wild theories?
As you know water Temp. currents and water depth play a part in the formation and behavior of a clone.
Great link below so you can monitor and track any cyclone or typhoon worldwide at any given real time.
By the way, the Dutch followed the roaring 40's from the Cape of Good Hope, but unfortunately they could not determine Longitude in those days, hence the number of wrecks on the West Coast.
Amazing Shot Craig.......
Please feel free to correct me on my ramblings with regards to barometric pressures etc.....and my north/south hemisphere theory...