Submitted by thermalben on Wed, 01/09/2013 - 13:06
After closely monitoring the BOM's Dangerous Surf Warnings over the last 5-6 years (and discussing internally, as well with a number of user groups), I think it's now time for an ongoing open discussion/monitoring thread.
Quite often they seem to be issued under scenarios that really aren't dangerous - or at least are not reaching the BOM's per-determined thresholds.
Right now the BOM have a DSW for Sydney beaches for today, tomorrow and Friday. In the south of the state, they have also issued a DSW for the Eden Coast for today and tomorrow.
Interestingly, the BOM have also issued a DSW for the Byron Coast today and Friday (but not Thursday).
Surf wise, there is a small/mod S'ly swell event due for much of the East Coast over the coming days but even wave model output is well below their thresholds. We'll see a peak of 3ft to maybe 4ft late Thurs/early Friday, but this will only be at south facing beaches. Locations north of Seal Rocks will see smaller surf than locations south of Seal Rocks (due to the direct southerly direction, and the origin of the swell near Tasmania).
In any case - three days of "Dangerous Surf" for Sydney beaches? I think not. Small/medium south swells of this nature are extremely common throughout the year. In fact off the top of my head (and without any data to verify) I suspect these kinds of swell wouldn't be too far off the climatological average.
The Byron DSW for today is very peculiar too. There's a small NE windswell in the water, and about 3ft of inconsistent E'ly groundswell (from ex-TC Freda) - both of which are below DSW thresholds. Definitely not 'Dangerous Surf' for the purposes of an official warning, in my opinion.
I'll post up a copy of the BOM thresholds shortly, but my version has the lower thresholds as Hsig of 2-2.5m with Tp of 14 seconds. Whilst Hsig is in this range (due to 25kts of southerly wind in the region), Tp is only 7.5 seconds.
The two nearest thresholds are either 3-4m @ 10 seconds, or >4m of ANY period - however there is another condition attached to these thresholds - the swell direction MUST be of an 'onshore' range (which the BOM stipulate for Sydney is 65-155 degrees).
So, with the swell direction currently out of the south, there is no way the current swell event will reach the lower boundaries of a DSW threshold in Sydney unless the period increases significantly.
FWIW, I think the thresholds are flawed anyway - peak period is not always directly related to the surf we see at the beach. A good example was yesterday, when we saw a faint E/NE signal from ex-TC Freda, which registered 15 seconds at the Sydney buoy (and produced very inconsistent 1-2ft waves). However, if this tiny pulse had occurred today - whilst there was concurrently a couple of metres of local windswell in the mix - the buoy readings would have theoretically triggered a DSW.
However, in this case the Tp figure is from a irrelevant distant storm whilst Hsig is related to a local windswell event.
In my opinion, a possible solution is that we should be using Tsig for DSW triggers, not Tp.
An interesting side note - I have never seen a Dangerous Surf Warning for any Vic, SA or WA coast, despite these regions regular experiencing very large/long period swell events (just last weekend, the Cape du Couedic buoy reached Hsig 5.5m/Tp 18 seconds!).
I have (once) seen a Warning for 'Damaging Swells' in Tasmania (during an enormous swell of 2011), but this was the only time.
As such, it seems Dangerous Surf Warnings are restricted to NSW and Qld coasts - probably due to population densities.
Without monitoring it myself, I will guess that this is happening more often during the holiday periods???
IMO it can be a good thing when you consider all the suburban and country people that hit the coasts over the holidays that have no real beach experience. It may make them think twice about entering the water especially outside the flags.
On the other hand, it can make some of us complacent because of constant undercalls. A bit like too many road and warning signs, you no longer see them or take notice as there are too many.
I have experienced clubbies up my way one xmas try to tell me to get my kids out of the water and that they were closing the beach. It was about 3' off the point and we were sheltered in the corner. I told him no, knowing full well he had no authority, to which he was suprised and pissed off. As my wife and I were at the waters edge watching them, I explained to him that my 4 & 2 year olds were under our direct supervision (they were in knee deep water) and that maybe he could discuss this with the parents of the other children that were lying on the beach with their backs to them. I told him that whilst I appreciated his concerns, I was not spoiling our morning at our local beach because of their inexperience in mild conditions. Don't get me wrong, they do a good job but they freak out once it gets over about 2'.
I guess what I'm trying to say is what the majority of us here already know and that is that what some consider dangerous, we consider to be normal or mild. Maybe those in that position are just becoming too affraid and cautious because of the "litigation" and "duty of care".
My suspicion is that these warnings are aimed at keeping rock fishermen who do not live on the coast away on days when the bureau perceives a risk and, for this group, a risk is anything around or above 3 ft particularly if the swell is inconsistent. Given that other warnings also seem to be manipulated it may be that they have a deliberate harm minimization policy rather than a commitment to absolute meteorological accuracy. If that's the case some public debate is definitely needed. I don't have any problem with it but I can understand how it might irk some.
The problem is that inconsistent 3ft days are very common along the NSW coast. If today's surf (3ft south swell) is worthy of a DSW, then in reality we'd probably see DSWs issued almost every other day of the year.
Otherwise it'll end up being a 'boy who cried wolf' scenario. People will start to become complacent and they'll be ineffective.
Also, each DSW should be more targeted. With a south swell building along the coast, many Sydney beaches won't see much of a size increase at all over the coming days (certainly not to DSW thresholds anyway). So, the warnings should be more specific.
Ben, a wee bit north of Byron today where I live - which is very exposed except for very southerly swell - it was barely tow in size for ants. I'd say 2 foot at best, perhaps very occasionally a tad bigger but you would not accuse it of being head high ie 3 foot normal scale (not Queenslander scale, which would be double).
I am not educated about the technical aspects that you have raised but I have thought over the years when seeing these incongruous dangerous surf warnings that sometimes they were triggered by what is usually reported by BOM as "sea" (as opposed to "swell") ie wind chop. That has been the only practical reason for danger I could see for the inexperienced on these occasions.
Nah, as per the chart above Mundies, it's triggered by swell parameters (initially model derived, and then confirmed by buoy obs).
The BOM also words the warnings as such (here's today's 'Dangerous Surf Warning' for Sydney):
"Dangerous surf conditions, hazardous for coastal activities such as swimming, surfing and rock fishing, are expected."
Well, there's three feet of south swell at exposed south facing beaches in Sydney today. Hazardous for surfing? Only as hazardous as every other surf day of the year. And although there is an elevated risk for rock fishing today (say, compared to a flat day) a 3ft south swell is common occurrence at any time of the year.
Maybe we need grades of risk (similar to UV ratings), or perhaps we should target specific activities? ie today would be a moderate risk for rock fishers, and low risk for surfers.
And, do we need a ocean swimming risk assessment? I'm undecided as to whether it's useful or not. As per a recent show on TV (60 Mins? 7:30 Report?) interviewing lifeguards on the Goldy, they noted that small days are often the most hazardous as the general public thinks they can handle the conditions (when the swell is big, people instinctively stay away from the water). Flash rips associated with a 2ft swell can be equally as deadly.
Here's a classic example of the other side of the coin - with the southerly track of Severe Tropical Cyclone Narelle, the WA BOM have issued a swell forecast for the Ningaloo and Gascoyne Coasts over the coming days as such:
"Seas and swell exceeding 8m."
However, they have not issued a 'Dangerous Surf Warning' for any WA coast.
There is however a mention of abnormally high tides/coastal flooding in their cyclone notes:
"Tides along the west Pilbara coast are likely to rise above the normal high
tide mark tonight and Saturday night with flooding of low lying coastal areas.
Higher than normal tides should extend along the west coast during Sunday and
Ben, of course you are right about the swell, and it was about 4' this morning at the south facing beaches I saw, and they pick up all the swell.
I suspect there are other factors they are taking into account. This morning saw a significant high tide, 3 -4 foot of swell, and all up a substantial amount of water movement, but not surprising given the combination of factors.
I don't know if they opened that beach, but I suggested to a local that it would be foolhardy to do so. It was fine for a surfer, but an absolute trap for young players. Lifesavers could have been out saving swimmers all day. In that respect I agree with fitzroy, in his comments about the number of inexperienced swimmers likely in the water (and also his comments about narky lifesavers - :-) )
The high tide would have meant that rock fishing would have been a much more dangerous activity than normal as well. Places that are usually out of range might have been dangerous today.
So while they have their guidelines, I suspect human intervention, and if that was the case I tend to agree with it.
But it's worth keeping a look out for future calls.
As for Ningaloo, I've been there. There is nobody out there for 1000kms that would have been surfing or swimming in local beaches. No point in issuing a DSW for nobody.
That's my take on it, uninformed as it is.
Thanks Ben. It was just something I postulated after living on the north coast nsw for a year or two and started noticing these warnings during feeble swell events. Only rarely seen them in South Oz or elsewhere and at these times it was totally appropriate. I am aware that heavy seas can be much more of a prick in a boat than heavy swell, so went my line of reasoning. Its fairly understandable for BOM to use computer models to do the majority of the grunt work but you'd hope there'd be adequate human oversight to make sure the boy who cried wolf syndrome isnt fed.
Re risk assessments - general ocean use vs specific activities. Now we are coming into an area I am familiar with. I think you'll find in the majority of applications where risk assessments are performed it is usually based on specific activities or tasks, otherwise its just not an accurate reflection of reality being too general. I like the idea of creating a risk rating for different ocean activities. I'm thinking it'd be a nightmare for BOM to administer though.
Forgot about this thread from 2013 (though DSW for southern states were discussed in the comments of a recent article I can't recall right now).
Anyway, I haven't been on the forecast bench for a week and a half, but it's worth noting that the BOM has Dangerous Surf Warnings out for the entire NSW Coast today. They're not in place for tomorrow, but are listed for Wednesday.
Wednesday looks like breaching the threshold but I'm not sure about today. Will be interesting to see what eventuates.
Was there one issued for the MNC over the weekend? As I saw footage of a good cleanup set on a fairly crowded rock ledge courtesy of that long period south groundswell on Saturday. fair bit of gear lost including backpacks, phones carkeys etc
Not sure as I wasn't around on Saturday (or Friday when the forecast would have been relevant). Sounds hectic though!
IMO local weather conditions should contribute to the DSW threshold. In stormy weather, the general public are less likely to go to the coast and meander across rocky points.
However, clear sunny skies and warm weather brings them out in droves and this is when it's all the more important to nail even small long period (and/or long range) swells as it's the inconsistency that catches people off guard, not the size.
It doesn't have to be twenty feet to cause problems (large swell events are somewhat self-regulating) - but a benign ocean will bring people down to the waterline, and it only takes an unexpected one metre surge across a rock platform to create serious problems.
BOM pulled today's DSW reference in their 4pm update. Looks like the forecast came in bang on Craig's prediction of 3-4ft across Sydney's south facing beaches.
Wed and Fri (and even Thurs, to be safe) definitely look like DSW thresholds though!
Another unusual event.
Early Wednesday morning (yesterday) I saw a tweet advising of a Hazardous Surf Warning for Southern NSW. This seemed odd as there was only a small background S'ly swell and a minor S/SE inbound swell in the water.
So I clicked on the link, and it provide more information: the warning was for Thursday (today). Again, this was unusual because relatively small surf was expected Thursday too.
Maybe they'd mistaken this for the long period S'ly swell due Friday, with the models showing peak swell periods of 18 seconds? Though IMO it will probably fall short of a typical DSW threshold (I'm expecting 4-5ft sets at south facing beaches, a somewhat common occurrence throughout the winter months).
Anyway, today is - as expected - relatively small out of the south.
I've also checked the Sydney coastal waters forecast, and the BOM have kept the DSW for today and also extended it into tomorrow. It's also on the general Sydney forecast too, which means it's being repeated during the radio/TV news bulletins too.
The big problem here is that we're looking at certain DSW event unfolding over the weekend and potentially holding for much of next week. So, these kinds of repeated false alarms can potentially have a negative effect.
Agreed that DSW for this region over the past few years Appear to have been too precautionary and often the huge waves are a no show. A sailor once told we that the BOM wind forecasts were more accurate with narrower forecast range prior to the storms that caused deaths in 1998 Sydney to Hobart yacht race. He theorised that BOM were playing it safe.
Ben! Thanx so much for questioning the 'suss' [Hazard Warnings]...Long overdue!
morg also deserves an explanation and salute for backing up Ben's gutsy call.
Yes! GC beaches were closed Yesterday / Today / Tomorrow & on & on & on...
Yes! There is a new BOM & it's confidential & pretty damn busy alright.
2013 BOM saw Climate Change as Front & Centre yet BOM as poorly paid Gods.
No better than scientists patching up radar with gum & a beggars bowl.
All secondary emergency services were paid premium in such events.
Meanwhile #1 BOM Godz cop the heat & are paid standard & laughed at on TV.
2013 BOM rallied OZ/NZ emergency services ANZEMEC.
2015 BOM Oz standard / 'supplementary' Warnings were formulated...
tbb believes Qld tested 'Hazardous Warnings' thru Qld/NSW 'Get Ready.' + NZ.
Qld has been running overtime Hazard Warnings 5 years...for sure! No Doubt!
2017 COAG signed off on a 10 year [ Hazardous Warning ] Supplementary Service
COAG BOM Forum meets twice a year.
Insurance can boss Govt's to adopt premium (Quango) Note every Portfolio is same.
Insurance can pay for supplementary to get ahead on Hot Spots.
Contract affords BOM to call [ HW ] eg: (42 hrs 'pre standard call time' on Hazard !)
Meaning a '42hr Supplementary' buffer added to 'Standard Event' forecast!http://www.bom.gov.au/marine/about/hazardous-surf-messages.shtml
GC Hazardous Surf Warning = 4 day Threat of Hazard+3 day mop up =1 week x 8/yr.
Meaning Beach is out of action for 2 months each year...about 40% dangerous surf.
Lifeguards are at a loss also...2ft no wind + Sun Shining [ BEACH CLOSED]
Apply same ransom to each Seachange town...all king pins will pay for answers.
BOM now overpower Qld Tourism & wiped out 'Aussies'- take down WSL easy.
Recent Goldie Xmas / New Year Heatwave saw a BOM Double Dip Ransom.
Mayor: 'You can all go home & take a cold shower & swim in your own pools.'
After Quarantine...The BOM virus was gone...well, for a month at least...now plagued.
BOM targets East Swell over South Swell...milking Yachties, Surfies are collateral.
Note: Cyclone Oma (Qld Premier : Please keep off the beaches ...& don't go surfing!)
News / Clubbies now condemn foolish boardriders as (Floody Idiots)
WSL ignore [BEACH CLOSED] (Maybe need Solid wave pool sooner than later!)
Yachties have CEO's caught in Ports...bribing anyone for elusive Marlin Selfie.
Not about Surfies... SEQ is Insurance #1 Grave yard...They own our Qld Premier.
Note this relates only to Natural Hazards... not Govt Toxic spills or Accidents.
Tsunamis - Bush Fires - Cyclones
Supplementary service if required on a dedicated basis for an extended period of time.
(General) Management Teams, Daily Updates, Texting, Training
The longer the duration...the extra the cost...(Best not to touch on recent fire windfall?)
Pause: Constant in Docs is extending services by intergovernmental bodies.
This in itself blows out Standard to "Supplementary reporting of Events"
Sure! We'll see a lot more of longer warnings for less reason.
tbb can only say that open ended loopholes are no accident by design.
BOM is to fund it's own upgrades & they make no excuses about how & why.
These are classified costs on classified self regulated scales...
At best, any accounting of real estimated cost blowout is stratospheric.
tbb is unsure if any watchdog department is qualified to price check our Gods!
BOM wants Premier League.
You see ECLs or Lightning Storms Toll can be reduced to Zero in Forecast Zone...
Riding up front with national security cavalry ( No Boats, No Drowning in flags)
BOM ( No drowning in ECL, No Lightning Deaths in CBD)
BOM prove they are Gods then reimbursed...Yes! Zero Toll is BOM prime directive.
[ Hazardous Surf Warning ]
Is premium by extending 'pre-warning' updates across all levels...BOM is Milking Jam.
Hazardous is Premier League Forecasting...Supplementary fees expand & paid.
Emergency Services Union / Sector would upscale 'Hazardous' pay rates etc.
Police Flood bonus rises faster than Floodwater, not just saying this.
eg: Lifeguards >[HAZARDOUS SURF WARNING] >[BEACH CLOSED] >[With Pay]
Mayor asks BOM when is it safe to Surf > [Supplementary Request] = $ BOM
BOM know unpredictable Coastline best & smell Seachange Gold mine.
Insurance walk unless #1 Costly Qld Govt / Mayors opt into classified scheme.
As said...BOM knew & designed supplementary service knowing this & more.
BOM's moment in the Sun, the Gods time to Shine...kicking sand in our faces.
2022 (5 year-Review)
2027 (Contract end)
Better get used to...[BEACH CLOSED] [BEACH CLOSED] [BEACH CLOSED]https://www.coag.gov.au/sites/default/files/agreements/Inter-Governmenta...
Good research there TBB, the joys of privatization I guess
For the record, today's surf size is close to forecast, if a tad smaller (3-5ft against the 4-5ft forecast) and definitely not near DSW.
The BOM has maintained the DSW for today and further extended it into tomorrow (though, tomorrow will probably reach the critera as a new E/NE swell starts to build).
As a side note, watching Graham Creed on the ABC last night, doing NSW weather - he said that there was as DSW in place for the Illawarra coast tomorrow (i.e. today).
No mention of any other coasts.
I totally understand that he's just presenting the information he's supplied with, but.... how is that in any way useful? Even if DSW conditions were likely, it'd be spread across a much broader spread of coastline than the Illawarra. They're rarely concentrated into small regions.
Cheers blackers...tbb has been dancin' around it for too long...Ben was bravest.
Crew could smell the bait packet...once Ben open it ...worms & fish heads, the lot!
Keep it up guys...mark off "FLOODWATCH" as another BOM Supplementary.
Gotta be another Quango in another COAG department...surely!
Supplementary: Non Bureau equipment...(Sat/Buoys/Station gauges/Mines/Toll Rds)
Recall when Councils privatised Water Meter Reading.
tbb stands by what he said...."42 hrs in Advance....?" is nondescript!
Examples show this to mean 42 hrs in Advance of "Standard Warning" not Event!
GC Hazardous surf warnings come 4 days ahead of event or non event mostly.
As said...purely a beat up designed to ransom towns under the pump from [FEAR]!
If it gets out...BOM will lose Climate Change cred...send OZ way back past 1950's.
Last few weeks, today are as chaotic as warnings go...(All smell Fear is the Key).
BOM have overstepped the mark & can't mop up the mess they've created.
Pre Warning Warning Track record is now clocking 60-80% miss...losin' cred hard & fast.
Now everyone has weather access...spot their Henny Penny game a mile away.
tbb says to pull the plug on it now...too bloody dangerous to play with Oz weather.
National Security Climate Change Henny Penny Medal nomination.
SLSA Patron Smoko awards Climate Change Hero Medal to Govt Head of BOM.
ACA (Tracy) "So BOM are leasing Cloud Banks to Whiteshoe Blue Sky Miners." Yep!
I was wondering when you were going to address this.
yesterday 1-3ft faces
dangerous surf conditions
i remember the internet when it was just for intelligent people but.
BOM probably playing it safe (legal liability) relating to tourists at spots like figure 8 pools getting caught out in flattish then going 4ft sets on the rock ledge, for example. Seen the vids of touros getting hammered?
Good call marcus & great comment page you started...best we link that.https://www.swellnet.com/forums/wax/485429
All are seeing the same shots being fired over the bow.
Bom bosses Tourists / Events / beach traders / Council Parking / Boat Charters
Occupations like Lifeguards + Volunteer Lifesavers + Surf Forecasters feel the heat.
Rec: No Boating, Swim, Nippers, Schools, Training, Hire-Lessons, Footy dippers
Surfers can smell the tide is turning & they too may face 2 months on the shelf.
Council Red/Black/White [no 'swim' signs] are regulatory eg: Penalty Points / Fines.
But These signs never once displayed (NO SURFING) with any Danger/Warning.
[R/B on W] Surfer ~ Sign posted for [Prohibited Area] never for Whole Surf.
However...NSW Red Flag a Series of 'new' [NO SURFING] Signs.
marcus...might need yer help with generic NSW photo...Newcastle-Ship/s ?https://fscomps.fotosearch.com/compc/CSP/CSP266/surf-closed-flag-on-an-a...
tbb can trace the (No Surfer) Surf Logo as far as 2015.(Ballina < > Newcastle)
This being the only rare surf danger sign [Surf Closed](swim)("Surfers")(Jet Skis)
tbb shows New 2017 BOM Hazardous Surf Warning now includes [ surfing ]http://www.bom.gov.au/marine/about/hazardous-surf-messages.shtml
Newcastle' Council Warning Sign reflects BOM directive > [No Surfing]
Cyclone Oma ~ Qld Premier & SLSQ Media directive reflects BOM > [No Surfing]
BOM / Premiers / SLSA / Council / Media instruct No Surfing in hazardous Surf.
Ask! How long ago did that last happen if ever?
Why Newcastle & SEQ ?
Recidivist Settlements are firstly shipping reserves...
Hazardous Surf Warning knocks out Shipping ...Foreshore is a Shipping Reserve.
re: US go overboard to twist the same sea law as total beach shutdowns forever.http://www.beachapedia.org/images/0/00/Surfrider_2019_Beach_Access_Map.png
Additional NSW Govt Coastal Surfing crackdown...Byron to Newcastle.
2014 [BIG SCARY SHARK SIGN] [Enter at own Risk]>[Water is Fine]https://c8.alamy.com/comp/FYD956/shark-sighting-sign-at-manly-beach-sydn...
2015 BIG [WARNING] (tiny shark pic) + [No Surfing] + Police hunt down surfers.
Ballina / Lennox / Coffs / Newcastle have all adopted similar [No Surfing] signshttps://www.goldcoastbulletin.com.au/news/council-to-warn-tourists-about...
2016-20 Signs [BEACH CLOSED] + (NO SURFERS).... (tiny shark)
(Govt Code): [Beach is soon ours]+[Surfers are banned]+[small sharks are fine]https://cdn.newsapi.com.au/image/v1/97f86d67944f03109453b5e8ef8bb605?wid...
2030 # \[email protected] On/_y #*~~/(C..x//x~/(C`..x//X [=SOLD=] + ['Silly! What's a shark?']
Perhaps the BOM folks thought that low pressure onion way off the coast of central Qld may move south and west, courtesy of a piggyback ride on a high pressure system sitting in the mid Tasman. One system blowing clockwise, the other anti-clockwise ... forecasting the result of that barometric mixup would not be easy. But you blokes know that, don’t you?
Synoptics, to my mind, inevitably give the best view of the weather, coming and going.
Cyclone Uesi Hazardous Surf Warnings...(Surfers Review)
SLSQ #1 Message
[ Lifeguards have Closed The Beach / Please Stay out of the Water ]
Default SLSQ +Weathermen > Big swell report is for Experienced Surfers Only!
Feb 13 2020 SLSQ (50 Boardriders were rescued in just one day at Noosa)
Seems like some tired after drifting 1km up the beach...re Vid.https://twitter.com/BOM_Qld
14 Feb 2020 Director Of Marine Rescue NSW
Warned Boaters, Fishermen, & 'Surfers' to avoid the Ocean in Coming Dayshttps://www.lakesmail.com.au/story/6630883/more-rain-coming-to-hunter-an...
15th Feb 2020 (Regional News statewide Message)
SLS NSW Hazardous Surf warning: Rock Fishers, Boaters, Surfers & Swimmers to stay away from the Water.https://www.9news.com.au/wild-weather/sydney-news-stormy-weekend-as-uesi...
Arguing that Rescues are grounded due to poor visibility, polluted seas & debris.
Same as 2019 Oma / Qld Premier personally instructed on News... 'No Surfing'...
Arguing rescuers can't risk further lives in Hazardous Conditions to rescue idiots!
When BOM play the Hazardous Surf Warning Card it now reads No Surfing.
SLSA are then to determine how that plays out with record Surfers in harms way!
BOM is a joke. Been comparing their forecasts against others for a long time. Never close to what's actually happening. Just the other week when we had 8-10ft out the ene they had on their charts the dominant swell as out of the south at half a meter! They seem to make a big drama when any long period swell arrives even if it's only 1-2ft.