Kallanguroo, well done on quite an in-depth analysis on the events of the day.

However, there are some things in it that I must point out to paint a clearer picture:

- After the event I had the opportunity of doing a bit of research on the Toowoomba catchments. The catchment of East Ck ( East Creek in flood ) is only 11.9sq.km. In relative terms that is extremely small and there would be hundreds of like catchments across Australia, granted not all feeding into a populous area, but plenty enough that do. So if you expect to see a flood gauge on this creek, then I would expect to see a flood gauge on every catchment bigger than 11.9sq.km where there is a real risk of flash flooding (we have three in town by the way).

- Next is the issue of timing. The above video has been shot approximately 5.3km downstream of the top of the catchment. That water is moving at considerable speed; there would have been less than half an hour before water levels reached a dangerous level. That means that to disseminate a warning in time you have to be monitoring the gauge (along with all the others you've installed that are under what was a very large area of heavy rain and assuming that it is reporting at a sufficiently regular time interval), assess it as being accurate (there's nothing worse than a 'boy-who-cried-wolf' scenario developing) and then get the warning out and into the community.

- There have been a multitude of readings of rainfall totals that have met and in some circumstances exceeded those experienced at the two official reporting stations in Toowoomba and that level of flooding has not been seen in those locations. Yes it seems now, with 20/20 hindsight, that these falls were very much at the lower end of the range of falls. But once again, by the time the higher falls were established it would have been too late anyway given the size of the catchments and the speed at which the flood developed.

I know the process of managing flooding risk quite well; we're just about to commence our second flood study and floodplain risk management plan for another village in our Shire. The process isn't as easy as you might think. The greatest hurdle of course is funding and while that should never be a barrier to a safer community the reality of the situation is that someone does have to pay for it; ultimately the community.

The other thing i forgot to mention was the murphys creek gauge was not working at the time. This creek height gauge is run by derm like alot of the ones you see on bom. This gauge could have given another heads up to the people downstream. In regards to rain gauges, it is well known that the airport gauge is in a rain shadow. It is common for the top of the east creek catchment to receive 50% more rainfall. Another rain gauge in the middle ridge area would be handy.

Great thread people
I had a rare lunch at home watching the posts listed above prior to the event and was seriously concerned and got home to the start of a tragedy, gutted
I wanted to post this comment before but this thread looks like a good place to do so, I could be completely wrong and have no idea (usual case) but wanted to share

Quote from WZ for Berrimah radar Darwin
"Path attenuation also occurs when the radar beam passes through an intense thunderstorm cell; the returned signal from cells further along that path will be reduced."

Was more happening to the west of "that cell" than could be seen from the Marburg radar and is another radar required further west or north west to fill the gaps
I frequently find up here a radar 300km south gives a more accurate view of what storms closer to me are doing due to "path attenuation"
Hate to see BOM lynched for this as they are a few hard working people while the WZ community is vast and large and no govt could afford similar
Great work all for the previous posts, hope this results in better preparation, planning and on ground resources for when the next rare event like this occurs

So Adam some creek height gauges are operated by DERM and others are BOM?

I assume there is no SLA (Service Level Agreement) on these things. If they are broke it's best effort response. We should recognise access for maintenance crews may have been difficult with this consistent falls this season.

I heard on ABC News 24 early Friday morning calls for an inquiry. On ABC Local Radio Campbell Newman has mentioned a forthcoming investigation as a follow up this evening, but Local radio are not ready to bring that subject mater up yet. Perhaps 1116 4BC will have the debate first, not really interested.

I've not heard anything from Queensland or Federal Governments on the subject yet. If they are smart it they will be on the front foot, and the Federal government should take the opportunity while ABC News 24 are running their continuous coverage nationwide.

The angle the media approach their coverage shifts every day. Nine started well (I do like their aerial footage) and have GEM simulcasts in trueHD during the morning, but have turned the content into Entertainment - a backyard blitz home renovation style coverage to suit the national audience.

Compliments for the detailed, extensive insight and contributions from others in this thread.

Can I raise the activity that occurred prior to any rain falling. The GFS trended to a firm probability of significant accumulated precipitation in the catchment for the start of that week.

So we have various issues as a postmortem, many of which differ to the lessons learnt of 1974. Perhaps we should collaborate on this list to come up with a set we believe should set the scope for investigation?

- To identify areas and types of new assets (gauges, radar etc) to get more "feelers out there".
- More engagement with the BOM <> Media, not just the duty meteorologist. We only see a minister when there is a new radar photo shoot. BOM should have community liaison / media relations type personell to be3 more involved.
- A need for stringent Governance over maintenance of assets (gauges, comms links).
- No central authority for responsibility (BOM are relying on 3rd party feeds).
- An ongoing lack of cohesion between the corporations and authorities who operate, own, govern and rely on the Dams in the catchment. This is a big one given they are a significant asset to our natural disaster mitigation plan (which we do not have).
- To extend the short-notice emergency broadcast technologies to regional towns and rural valleys, perhaps using fixed loud-hailer type speaker installations similar to fire warning sirens.
- To find some middle ground between city forecasts and warning/watches, or have more rigorous cross-checking of forecasts (perhaps people were on summer leave).

Here's my synoptic on the environment that took away those lost souls at Grantham having studied this extensively. I'm keen for confirmation if anyone has Monday's river height archives (they are just out of retention on wwwbom site).

Firstly, if you have not already, check out Chops Radar it will show you the weather radar for Monday and Tuesday and I will talk you thru it:

Grantham Sits on Sandy Creek which receives flows from the north of the town. It is also adjacent to the Lockyer Creek which bypasses the town along the southern outer perimiter of the township.

Soon after the Toowoomba Mid-monday flash flooding, the Lockyer Creek (located to the south of Grantham) was flowing as shown in this footage from Helidon.

Overnight on Monday, the Helidon Guage on Lockyer Ck was hit with debris as a result of heavy inflows from Toowoomba's flash flood earlier that day. That resulted in data being suspect and it's readings were since removed from the BOM web site to prevent distribution of mis-readings. It would be great if the BOM can release this data to us. I cannot even go back in time on webarchive for some reason hopefully it is not Conroy web filtering conspiracy The Helidon Guage is the nearest upstream guage from the Grantham township.

Late Monday night the catchment was specifically targeted as further heavy rainfall patterns came through slightly east in alignment to that of the previous morning. This alignment was directly over he small Sandy Creek catchment, which is the main creek running thru the Grantham Township. The Sandy Creek Gauge on is very close to Grantham township which does not allow suffcient time for alerts to be detected and communicated to the township (as mentioned). Note that guage shows two significant peaks being 10AM and 4PM on Tuesday as a result of that Tuesday morning rain that saturated the creek's catchment. This this similar to an "eye of the cyclone" effect.

Thoughts with those who were taken.

I posted this in the other thread the other day so will add it here...this was a WARNABLE event - and I've also made some comments about the operational use of radar that you may be interested in Kallanguroo.

--------------------------------------------
Hi Guys,

In regards to forecasting this event...

I've worked as a meteorologist for 9 years now (I worked part-time through uni when I was studying meteorology). On top of this, as many as you know, I specialise in forecasting of storms and severe weather events (for a wide range of clients, some commercial, some not so). One part of experience I find invaluable to storm forecasting is the fact that I also chase storms - this means I get to see the radar and correlate it with how things look visually, and how they're occurring on the ground.

In my experience, I've learnt that radar often underestimates intense rainfall IF THERE IS NO HAIL. This does make sense because ice reflects intensities much stronger than water drops do. Furthermore, Doppler rainfall rates are actually very correct in these scenarios. I've had discussions (read disagreements) with a few Bureau forecasters on this who all believe Doppler over-estimates and Marburg is correct. Again - this is something I've learnt from being on the road studying, chasing (and in some cases, researching) thunderstorms. I've seen the reflectivities of both radars and experienced what they produce - literally hundreds and hundreds of storms and showers for both.

From that experience, I could deduce that the large storm which showed moderate to high reflectivies was without a doubt dumping massive amounts of rain (compounded by slow movement). This wasn't an ordinary storm - even the overall shape and development was different to the usual "large storm blobs" you see on radar. Unfortunately, this appears to have been overlooked by the Bureau.

Another factor overlooked was how saturated the ground was. It meant that any rain that occurred, simply ran off. Not to mention - any dams would have been full. And perhaps a compounding factor in this is that severe erosion from flash flooding around dams may have compromised several private dam walls which added to the surge of water.

Combining the above two factors (likely falls in excess of 100mm in a short duration over a large area in the same catchments) to me meant the possibility of not only flash flooding was high, but very dangerous flash flooding was high! Hence my posts earlier in the Forum outlining we might see a very concerning situation unfold in the Grantham/Gatton area in the coming hours as the water rushes down the hill.

But perhaps the most unforgivable thing was that one hour after the huge peak in the flood spike at Helidon occurred, the Bureau issued a warning for the Lockyer Creek with no mention of this spike. This clearly shows that the situation wasn't even being monitored, and you cannot say that the Bureau thought it was erroneous because there were TWO DIFFERENT flood gauges that reported similar peaks! It seems that the equipment soon failed from this.

Regardless of residents' actions - they deserve to know they're in danger. Whether people heed warnings or not is irrelevant (but this also brings about my final point - a point that I bring about a lot. There is no official way of elevating an emergency warning in Australia. Media are slow to respond (lets face it, an hour is too long in an emergency). There is an excellent system available through the Early Warning Network which isn't used to its full potential by government. Perhaps in the future they'll look at better trying to integrate ALL available resources (this means private as well as government) to try and co-ordinate warnings to the public in these extreme events.

Hopefully this provides some insight from a meteorologist's point of view on the event...

AC

This was just posted this morning on ABC. It would be good for all of us on the WZ forum here to be able to present all what we can to this inquiry. Anna Bligh, Campbell Newman, the coroner etc etc need to get this info especially with the time line that has now been established.

Inquiry must wait for normal life to return: Bligh

Posted 18 minutes ago


Queensland Premier Anna Bligh says it is too soon to be calling for public inquiries into the freak flash flood that claimed lives in Toowoomba and the Lockyer Valley this week.

So far southern Queensland's flood crisis has claimed 16 lives, 20 people are still missing and police say some may never be found.

Ms Bligh says an inquiry will have to wait until life starts returning to normal.

"I am as keen to find answers to some of the questions, particularly about the Toowoomba event right now as [anyone]," she said.

"We are still getting basic essentials to people, and until that job is done that is going to be my number one focus.

"But yes, looking into all of the background of this event is something that we will be doing and we will be doing it in a public, transparent way so people can participate."

The Lord Mayor of Brisbane, Campbell Newman, wants a judicial inquiry into the flood crisis.

Mr Newman says many residents were taken by surprise by the speed and extent of flooding.

"There does need to be a good look at this down the track: about how we can better protect Queenslanders, early warning, town planning policies," he said.

"I don't really want to address it more than that [at this stage], but it's the right thing to do."[i][/i]

Also note in thread initial SE QLD Flood thread: http://forum.weatherzone.com.au/ubbthreads.php/topics/920790/103

@ 12:16pm EST
------------------------------------------------------------
Concerning for the Gatton-Grantham area right now with that very large storm/rain area moving towards it with no doubt, torrential rainfall! Sandy Creek (in Grantham) has caught quite a few people by surprise and I hope they're prepared for it, but sadly I think most won't know until the water starts lapping up at their homes due to our insufficient warning system.

Event is definitely not over - the dry slot is there, but the moist air in front of it is the danger zone which is what's passing through/moving towards Southeast Queensland right now! Not to mention the instability - and radar is certainly showing a clear picture of the instability right now.

AC
____
------------------------------------------------------
@ 2:34pm EST

This is my concern too - that there's going to be a near wall of water flowing down into the communities through there...

The flooding in Toowoomba would be significant too with 60mm in the last hour.

The satellite images seem to be hooking the cloud more westerly now which if that's the case, would begin to drag the rain and storms offshore back onto the coast.

AC

-------------------------------------------------------

@ 2:41pm EST (from Nellie1969)

Gary on Radio 4BC just read out a list of emergencies happening in Toowoomba at the moment due to that 'cell' that has just hit it. Apparently people are missing, landslides occurring. Several cars including police cars are underwater.

Edit to say: Neil Stewart a TWBA resident has just called into the radio station. At the moment there is no way into or out of TWBA with landslides/flooding occurring. People trapped inside a fruit shop, they are apparently hanging onto poles waiting to be saved. Cars with people trapped inside them and helicopters have been called in for emergency rescues. He will be back on 4BC after 3pm with full details. This has all happened in the past hour apparently.
--------------------------------------------------

That's hours before the first reports came in!

One thing I have noticed on this forum and others, that many will hop on with an intention to post with something they feel strongly about, they may read the last post only and forward their opinion without a thorough dissection of the previous posts or pages.

Sometimes the post are so quick you cant keep up and there is an over sight. But just reading one of the current posts, I must clear the air and refer you to AC comments. In reading other posts you will see THERE WAS ENOUGH TIME TO ISSUE A WARNING, please also refer to the time line by Andy Double U, the post that Adam Ant did on this thread, and without knowing I posted a similar one myself that can be found here http://forum.weatherzone.com.au/ubbthreads.php/topics/927214/44.

Just a tech question, why is this thread from page 3 now called ??????????????

Re: TGIF BrisVenice - Let's go back to Sunday, how did this all happen? [Re: UHF_CH10].

Just hope no one can hack this thread with all the tech on it. It is going to be useful information.

Can WZ back it up and protect the integrity of it??

Coltan, in the full reply form you can change the subject of your post. I'd say this is what someone has done.

Team, the subject change was unintential my me I was presented the option when adding a post to specify a subject (field was presented). I had expected it to only be bound to my post, not rename the thread. If this is unexpected behaviour of the platform then Mod should verify when using "Switch to Full Reply Screen" that the subject field is not presented as it was for my account this morning.

Regards
Brendan H
Morningside
0458 082 936

The Burtons Bridge and College's Crossing gauges have also been removed - they failed shortly before they peaked (I know because I was monitoring them constantly)

Nice try at getting your point across on ABC talkback early this morning UHF CH10...but I think I was missed ..

This event will change the way warnings are isued and diseminated but I think it could take a year or 2 befor we see any real change ,unfortunatly ...

I think things realy need to be acted on a bit quicker as this season is far from over and as we have witnesed in other parts of this and other states repeat after repeat flow ..

take care and best wishes to all effected sofar and ahead..

cheers

Thanks Michael sorry I did notice it had applied to the thread but was heading out the door for recover duties so did not have a chance to advise.

I think the public will be demanding a terms of reference get put together pretty quick.

I do not want to shout conspiracy here and realise we need to withhold this for a certain period of time during recover, however the media need to tell the truth today. If it is prolonged beyond today, the river height graph no longer show what happened on Tuesday. I understand we have to land this softly and protect those impacted, however how much longer should we keep the friends and family of this township of 200 in the dark? Can we not take the opportunity as a lesson learned to identify we have the tools and technology, we simply need to encourage people to use it!!! The current approach of locking this up in the cupboard and wrapping it in cotton wool only prolongs the misery of the situation.

Yeah alot of the river gauge heights you see on the BOM website are run by derm or seqw. Here is derms gauges http://www.derm.qld.gov.au/water/monitoring/current_data/map_details.php?group=brisbane

Please note that the Murphys creek station has not been operational since Nov 3 2010.

I remember scaning river levels that evening and came across a spine-chilling reading. I am pretty sure it was the Helidon gauge. I think major flooding was classified as 4.3m but that day it was up to 12+m. I so hoped it was a false reading, because 8m over major flooding in 1.5 hours seemed impossible. The next day Helidon gauge was not on the list anymore.