Category Archives: Water

Dubious BoM claim about Brisbane rainfall – “Wettest May day in 175 years” – thats the 2nd of May 2015

Fairfax are running this story Brisbane weather: Wettest May day in 175 years
The claim that 182.6mm on the 2nd May represents the “Wettest May day in 175 years” is not even technically clean because many early years had no data – so the 175 years is shonky. But let’s ignore that. Facts are that rain data are so noisy that any claims based on one station need examining. In this case on 2nd May 2015 for the BoM’s own rain district 40 South Coast Moreton & Brisbane.
These stations exceeded the 182.6mm figure. I have tried to avoid the higher altitude stations which have heavier falls.
ALDERLEY (040224) 252.4mm
BOONDALL (040531) 213.6mm
CALAMVALE ALERT (040784) 186mm
DECEPTION BAY ALERT (040980) 278mm
HILLTOP GARDENS (040911) 209mm
MORAYFIELD ALERT (040979) 296mm
PEACHESTER (040169) 269mm
TOMEWIN TALLOWOOD (040899) 187.4mm
WATERFORD ALERT (040878) 193mm

Let’s look at a four day period 2nd to 5th May 1996 – there may be others but my time is limited –

I think by any standards the 2nd to 5th May 1996 swamps any record claimed from 2nd May 2015. Count some of the 4 day totals.

Media spreads fairy story that Caboolture and north Brisbane floods were a once in 2000 year event

More likely a once in two years event. Queensland storm: Five dead in storm called ‘one-in-2000-year event’
I saw this headline – Thats why our homes flooded

Queensland storm: Residents of Deception Bay claim Moreton Bay Rail Link works contributed to homes being flooded
Interesting to read the comments in both articles – most seen realistic.
I was surprised to see on TV news video of quite modern houses built along what became a raging watercourse. Looks like Qld town planners need to learn basics about flood prone areas.

Australian Bureau of Meteorology claims Caboolture rainfall is “off the scale” – yet their own maps show higher daily totals in May 2009

Fairfax media reports – Brisbane weather: ‘An extreme weather event’ takes five lives – The ABC reports – Queensland weather: Five people killed after three cars swept away by floodwaters; storm moves into northern NSW
A BoM contour map shows the rainfall to 9am on 2nd May – this map is for 20 May 2009 – note the higher rain contouring into the purple zone.
The 7th, 8th and 9th of May 1980 had heavy rain in the Brisbane region too. Note I have only scanned for May rain – there would be many more floods if I looked at all months.
I have not yet seen numbers convincing me that the last couple of days was worse than 2009 – and daily data is very poor for the earlier in the 20th Century.
There are many more rain gauges now but data is not easy to access. This AWN site is useful for eyeballing daily rain at the many Brisbane region stations. Here are the rain maps from above BoM links to compare for yourself –

Purple is above 200mm per day
Dark blue is 150-200
Light blue 100-150.
Obviously the station data is more spotty than the contour maps – and BoM computing has to somehow average to get the contour positions.

Australian Bureau of Meteorology rain Outlooks – failure looming in March and flip-flop confusion for April

In late February the BoM forecast March and April rain as follows.

Now rain to date for March (1st to 26th) shows Australia was wet in the west and dry to average in the east- sort of exact opposite of the above March rain Outlook.

Now note the February Outlook for April in top panel forecasting a dry April.
Contrast that with the new April rain Outlook just issued forecasting a widespread wet.

Who could believe a word the BoM utters when they keep changing predictions.

Is the media over-reporting the Twiggy Forrest campaign to better use water resources in northern Australia ?

The ABC reports – Andrew ‘Twiggy’ Forrest calls for harvesting of rivers, underground aquifers to droughtproof agricultural areas. They report – “Mr Forrest wants to droughtproof Australia.” It reads to me like a push to exploit water resources in the north of Australia and I am sure more could be done along those lines. The coalition was talking about using northern water resources in early 2013 – that seems to have sunk lately.
Good luck to Mr Forrest pushing his ideas but we are light years from achieving sensible water reforms. The Murray Darling Basin plan still proposes to waste huge amounts of water to flush the Murray mouth, pandering to South Australia.
Just look at the waste of Melbourne water supply Thomson Dam water by environmental flows – 35% through the dryer years 2002-2009. Any proposal in the north will meet trenchant opposition from several well known quarters. I doubt any serious projects could get up with our MSM so GreenLeft.

Australian Bureau of Meteorology predicted a dry January but it turned out very wet

A major rain event starting in Alice Springs ~7th and running about a week destroyed the BoM dry prediction. I have not seen a reason quoted for that – did the jetstream wobble – for sure the moonsoon belt fired up to the south. I wonder how useful this rain Outlook was.
January rain Outlook

January actual rain percentages – you can make maps of other parameters