From the “more facts against the Mann” department. While claims of climate change swirl about from the usual doomsayers, such as this one from Time Magazine:
Climate change is making rare weather events less rare
At least nine people have died in flooding across South Carolina that has left city streets submerged in water, destroyed homes and closed more than 100 bridges. Nikki Haley, the state’s governor, described the disaster as one of such an epic scale that science suggests it would only occur once every 1,000 years.
A flooding disaster of this scale was unlikely to be sure, scientists say, but climate change has transformed once-in-a-lifetime events into periodic occurrences. The flooding may have been hard to predict, but it should no longer come as a surprise.
And everybody’s favorite poster boy for disaster, Michael E. Mann, says at the Washington Post:
This is yet another example, like Sandy, or Irene, of weather on “steroids,” another case where climate change worsened the effects of an already extreme meteorological event. In this case, we’re seeing once-in-a-thousand year flooding along the South Carolina coastline as a consequence of the extreme supply of moisture streaming in from hurricane Joaquin. Joaquin intensified over record warm sea surface temperatures in the tropical Atlantic, which both allowed it to intensify rapidly despite adverse wind shear, and which provided it with unusually high levels of moisture — moisture which is now being turned into record rainfall.
Really? As Bob Tisdale pointed out here a few days ago:
In fact, the sea surfaces along the {hurricane Joaquin] storm track were regularly warmer in the 1940s and 50s than they have been recently.
Clearly, Dr. Mann is all wet.
There is also the claim being tossed about that there’s more water vapor in the air due to global warming. There’s no support for this idea in the satellite data:
The NVAP-M project shows total precipitable water (TPW) data is shown in Figure 4, reproduced from the paper Vonder Haar et al (2012) here. There is no evidence of increasing water vapor to enhance the small warming effect from CO2.
Instead of “steroids”… a more mundane explanation has emerged from satellite imagery: a river of moisture, aka an “atmospheric river” much like we get in California from time to time, which we call the “pineapple express” due to the origin of the river of air near Hawaii. Wikipedia defines it as:
Pineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent flow of atmospheric moisture and associated with heavy precipitation from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America. A Pineapple Express is an example of an atmospheric river, which is a more general term for such narrow corridors of enhanced water vapor transport at mid-latitudes around the world.
…
Early in 1862, extreme storms riding the Pineapple Express battered the west coast for 45 days. In addition to a sudden snow melt, some places received an estimated 8.5 feet of rain, leading to the worst flooding in recorded history of California, Oregon, and Nevada. Known as the Great Flood of 1862, both the Sacramento and San Joaquin valleys flooded, and there was extensive flooding and mudslides throughout the region.
Get that? A “meteorological phenomenon” not a climate phenomenon. And, the confluence of meteorological events that led to that situation happened well before “climate change” was a glimmer in Jim Hansen’s eye. Even the normally pro-warming Capital Weather Gang say the flooding in South Carolina is a “very complex meteorological event “.
“At least eight key elements conspired to create a highly efficient, small-scale rain machine centered on South Carolina,”
Some meteorologists have been calling this plume of rain a predecessor rain event, or “PRE,” which sometimes occurs ahead of tropical storms that interact with separate areas of low pressure and lingering surface fronts — exactly what Hurricane Joaquin did. – Jeff Halverson at Capital Weather Gang
The reason things get complicated is that the heavy rains over South Carolina are a confluence of multiple causes, that low to the left, Hurricane Joaquin to the right; the atmospheric river tapped some of its tropical moisture and the low spun it right into South Carolina.
Clearly from this NOAA GOES satellite image of water vapor content, we have a meteorological phenomenon that is a rare confluence of meteorological events that resulted in an atmospheric river:
Added: h/t to Willis Eschenbach for the video clip
At same time at the opposite side of Atlantic (actually in Mediterranean, at the Cote d’Azur, S. France) a short burst (just 2 hours) of intense rain killed 17 people. However, this was not one in the 1000 years event, but 3rd in the last 5 years, although in the two previous ones (2010 and Nov. 2014) the mortality was not so high, if I remember correctly.
While the worry warts were warning of the current hurricane of concern, that was heading out to sea, the actual live weather geeks, were telling their audiences, that the current disastrous Carolina flooding was entirely due to well understood weather events that are completely unrelated to the hurricane.
The consequences for the people of the region are very real, and we all feel for them on that, but it is unrelated to this Joachin storm.
Vukcevic, that part of France is notorious for flash floods due to the terrain. Common events and time of day has a bearing on casualty numbers.
Yes, I know it well, I left only 2 days before, but waded through the last November one, at least this time the storm wasn’t accompanied by strong winds.
Um, how does one arrive at the conclusion that this was a once in a thousand year flood?
It’s in the Noah’s ark log book.
Aah!, the ONE signed by God!
Did they keep wooden bucket temperature measurements back then, by dipping their fingers in them? We might be able to calibrate Argo buoys against them if so.
Clay pots , Phil. And they stuck their tongue in…more sensitive.
Same way they checked for voltage.
Pulled it out of her butt. Veracity doesn’t matter; all one needs is a sensationalist sound-bite to spread across the TV media.
Somehow, I believe that is what happened. Media folks called around until they found someone prone to a bit of hyperbole saying this is a 1 – 1000 event. Its like telling that girl she is one in million, until you dump her for the next girl who is also 1 a million (what are the odds of all one’s girlfriends being one in a million!)
If you live in China, and are one in a million…there are 1360 just exactly like you.
But, as for the girl friend thing, they are all one in a million, just a different one.
I saw an interview with a resident of South Carolina. They were standing in water knee deep in front of her house which was built on stilts, the carport underneath, the house proper two stories another fifteen feet up.
If it only flooded there knee deep once in a thousand years, why the stilts?
I believe the way it goes is you take the rainfall, calculate the number of standard deviations away from normal it is, and the area beyond that point in the Gaussian bell curve is the likelihood of the event being exceeded.
Folks are talking about needing a different shaped bell curve to handle extreme weather events, as the “one in xxx” scheme doesn’t work out well for events in the tails of the curve. When a place gets hit with a once in a century storm one year and again a couple years later, it’s clear the tails need to be pulled higher.
Or go ahead and build your condo. It’ll be safe for 200 years? 😎
Ric: “When a place gets hit with a once in a century storm one year and again a couple years later, it’s clear the tails need to be pulled higher.” The “once in an XXXX year storm” is a probability statement. Think of it as a recurrence interval. The probability that a storm of that “magnitude” in any given year is the same for each and every year. Hundred year floods have a probability of 0. 01 (or 1 percent). It is a measure of flood magnitude (volume, flow rate, etc). Just because it is a once in a thousand year flood does not mean that you could have another one next year or even another one this year. Each year the probability is the same.
Well since he bell curve is based on the information you have; you said rainfall, all that calculation gives is how many elements you would need to have in that set, to have one of them that far out in right field. It can’t tell you anything about events that haven’t been observed yet. (didn’t occur already).
Why do people infer prediction of the future from information that is only about the past that is already known??
It is like if you flip a 1000-sided coin.
Ric, that’s correct – fit a Gaussian to the observed data over your POR (period of record), and then go out on the wings for the probabilites over many more years. Sounds good in theory, and seems to work well for some things (like rolling dice). But here’s an anecdote using observations from my very own NWS co-op station.
I started obs. in 1982, and after 20 years figured I had enough points to draw that Gaussian curve. One thing of interest is heavy precipitation events, of course. There were several 4 to 5 inch events in those twenty years, and that Gaussian came up with a return interval for a 9-inch event as 6 million years. That would be ten such events since the dinos died.
The following year there was a 9-inch precip event (falling as 72 inches of snow!!!), and suddenly that 6-million year storm became a 21-year storm. Well, not really. Re-computing with one more year of data came out to once in 20,000 years.
Fast forward a dozen years: two years ago there was another 9-inch event. Re-calculating makes those 7,000 year events.
Then I found a guy up the hill who recorded a 12-inch rainfall event in 1969. If I put that into the calculation, a 9-incher becomes a 100-year event, and that 12-incher a 44,000-year storm (even if it happended only 46 years ago).
So that silly Gaussian still says an event that’s observed 3 times in 44 years is a once-in-a-century storm. Apparently there’s a population of extreme events that are disconnected from the normal well-behaved everyday storms.
Maybe rainstorms aren’t Gaussian. Ya think?
BTW, that 72-inch snow was the biggest in 33 years of record. The Gaussian says it’s a 330 year snow, and only had a 1 in 10 chance of falling on my shift.
For disasters like this, statisticians use the Poisson Distribution. This distribution allows for disasters to occur in groups of 1, 2, or 3 occurrences over short periods of time.
Richard Keen,
Wow, I never had any occupation lie what you describe, but just following weather events as a hobby, and making certain inferences, I came to the same conclusion you seem to have done re extreme precipitation events being a separate mechanism from normal everyday weather.
I wish I was better at describing what I am thinking.
NOAAProgrammer,
I never knew what a Poisson distribution was (I thought it was some kind of soup), but this seems to fit observed events far better than Gaussian distribution.
No. For flood peak estimated return period you following the following procedure, or one nearly like it. You rank the data from highest to lowest and assign a probability to each with the largest event having the smallest probability. This is usually done from USGS streamflow records, but sometimes other agencies do stream gauging as well. Then you fit a probability distribution to the observed stream-flow annual peaks (or partial duration series). Now that you have the probability distribution for flood peaks, you extend it (extrapolate) until it reaches the flood peak you observe or estimate for the storm of interest. Then you estimate the exceedance probability for that large flood and calculate the return period from the estimated exceedance probability. The farther you extrapolate from the largest flood peak recorded, the higher the uncertainty in the 1000 year flood. Consult USGS methods reports or almost any hydrology book.
By declaring that it will never happen again until 3015 in October.
g
Richmond, VA has had four of those 1000 year events in my memory; Camille in 1969, Agnes in 1971, a massive line of thunderstorms upstream in 1972 and Gaston in 2004. Agnes brought 36′ 9″ flood height, Camille 35’+. Gaston dumped 10-12 inches in roughly five hours. I vaguely remember other floods in the early 50s, but nothing like Agnes and Camille.
You just take the rainfall measurements that you do have going back 100 or more years and well established stats theory will provide an ‘estimate’. Remember you can more than 1 such event in the time period, and its not impossible to be say 50 years apart. The actual way is should be described as a probability, ie 1 in 1000 chance
Yes, you are technically correct, but I think some reporter just found some excitable meteorologist who proclaimed in his excitement that it was a 1000 year event. I highly doubt much math really went into it. And I also find all the 100 year events that happen every year suspect – like someone with an agenda is trying to make the weather seem more extreme.
…so we have an all clear for another 1000 years!
Khem … “Um, how does one arrive at the conclusion that this was a once in a thousand year flood?”
Obviously, an AGW believer/weatherman gave Gov Nikki Haley that propaganda line, and Haley, not knowing she was repeating crap propaganda, used that line in her press conference. As governor, she is considered an authoritative voice so it has been repeated ad nauseum.
Just like estimating 1 in 100 yr events. Take the time series we have collected, fit the rainfall totals to a statistical distribution (log normal would probably be close) and identify where the current event falls on that distribution. Insurance companies have used this approach for years to set flood insurance rates.
Tony Heller/Steven Goddard at realclimatescience.com has a wonderfully succinct explanation of the probability factors:
“Every time we get a big rain in the US, climate morons start claiming it was a 1,000 year event
So what are they doing wrong?
Your odds of winning the lottery are very small, but the odds of someone winning the lottery are quite high. What these geniuses are doing is conflating the odds of one individual station getting a 20 inch rain, with the odds of any station getting a 20 inch rain.
Big rains are not rare in the US. Alvin, Texas got 43 inches of rain in one day in 1979.
We heard exactly the same 1,000 year nonsense after the 20 inch rains of 2013 in Colorado, but Colorado got 24 inches of rain in six hours in 1935.”
Extreme weather is always happening SOMEWHERE. That’s normal, not exceptional
Reagan invented the term on the occasion of the ’64 floods in N. Cal. There were earlier floods in ’55 that then governor Pat Brown declared as 100 year floods. Reagan one upped him when much bigger floods occurred only 9 years later.
This event might not be caused by 100 ppm of CO2, but events like this could become more common in a warming world, dontcha know. So be afraid, and send money.
Exactly. Governors know to start lobbying for a federal bailout early by inflating claims and causes. So yes, this is like $uper $torm $andy.
On average, super storm Sandy didn’t do much of anything. For most of its life it was ho hum.
They just cherry picked a few days when it was ashore in the US, and caused some problems. In terms of climate, we will have to wait another 30 years to find out what SSS actually accomplished.
I was in the middle of Super Storm Sandy and it washed out 100 year old bridges in my little town of Berlin, NY. It flooded everything and did a lot of damage. Belittling this big storm is harming your own arguments and looks bad.
Charleston is built on a substantial river delta, and river deltas are built through periodic flooding.
If you get a really hot blonde meteorologist to report it as a result of global warming, everyone will believe it, or not care to say otherwise.
Or you could get Heidi Cullen to say it, and then everyone will know it is a bunch of malarkey.
Ouch!
/sarc off
Historic flooding? Unprecedented? Then why did Noah build that ark?
Seriously, they picked Columbia, SC, and said there had never been 10.x inches of rain there in 24 hours before. Ever. Since the creation of the world, or since records have been kept (whichever is more recent.) But I know damn well other locales in SC have recorded that much rain before in a day. Just ask anyone from anywhere in the SE USA. “Boy, you don’t know what heavy rain is unless you’ve been in one of our gullywashers! Can’t see your hand in front of your face.” The cherrypicking of local records is histor…, er, hysterical.
Last Saturday’s SE. France had 7 inches in just 2 hours, so 10 inches in a day doesn’t sound too extraordinary.
We’ve had 7 in of rain in the lee of western Lake Ontario in less than a day, 2 or 3 years back Yup, got some flooding.
I was programming for Joe Barnes at NOAA in Boulder, Colorado and Doug Lilly of NCAR when the Big Thompson Flood of 1976 killed 143 people – the worst in Colorado history. The first day at work after the flash flood, I remember Joe and Doug saying, “heads are going to roll” because this was not predicted.
But when the weather maps were closely studied it was concluded that the weather coincidences were so unusual that no meteorologist could have predicted it in advance. As I recall, the wind vectors of 4 different weather systems “canceled” one another out, causing a thunderstorm to stall over one of the high Rocky Mountain basins and dump over a foot of rain in a short period of time. A wall of water up to 20 feet high funneled through the narrow Thompson Canyon draining that basin.
Stationary thunderstorms that rain themselves out in place are an everyday occurrences here in Florida in Summer.
I have had three separate ones at my new place that i have only lived in for about 28 months.
Each caused nearly 8″ of rain in a few hours. Two of them happened on consecutive days last summer, leading to localized flooding in a two or three block radius, but dropped zero rain beyond that.
Even with porous sandy soil, that much rain takes a few days to soak into the ground…little of it runs off in my area…not enough slope, and many roadside swales are poorly graded.
noaaprogrammer says: I was programming for Joe Barnes at NOAA in Boulder, Colorado and Doug Lilly of NCAR when the Big Thompson Flood of 1976 killed 143 people – the worst in Colorado history. The first day at work after the flash flood, I remember Joe and Doug saying, “heads are going to roll” because this was not predicted.
I remember that well, too. Worse than the forecasts was the downtime on Limon radar for regular maintenance, so not only was it not predicted, it was not detected (until…). I don’t think any heads rolled, but Fernanado Caracena and others pieced together the similarities between Big Thompson 1976 and Rapid City 1972 and put out a wonderful paper that has resulted in successful forecasts of mountain area flash floods ever since. Hundreds or thousands of people are still alive today because of that work.
So no heads rolled, and hundreds of others were saved.
Richard K
Many thanks.
An excellent outcome.
If you could paste a link to the paper it might allow current practitioners to see what old folk used to do – that worked. . . . . . .
Mods – well – perhaps a soupcon of sarc/
Auto
Auto,
I’m most familiar with the NWS Tech report version of the paper, which emphasized forecasting lessons from the storms. But a closely related version was in Monthly Weather Review as:
Fernando Caracena, Robert A. Maddox, L. Ray Hoxit, and Charles F. Chappell, 1979: Mesoanalysis of the Big Thompson Storm. Mon. Wea. Rev., 107, 1–17.
doi: http://dx.doi.org/10.1175/1520-0493(1979)1072.0.CO;2
Free at:
http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281979%29107%3C0001%3AMOTBTS%3E2.0.CO%3B2 and…
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281979%29107%3C0001%3AMOTBTS%3E2.0.CO%3B2
Good stuff. Real weather research that saves lives and homes.
If you could just get all that precip upsloping and training when it is cold enough at your house then you could finally break that all time one day snowfall record! 🙂
We lived in Louisiana during our study for the Master’s degree (my wife) and the Ph.D. (for me), a period of a few years and a couple of shorter times. Some years ago A. J. Liebling wrote a wonderful book called “The Earl of Louisiana,” about Gov. Earl Long, a most memorable character. (A story about Earl a few lines down.) Liebling went down to Louisiana to live for a while and to observe the state and its statesmen, including Earl Long. He lived through some memorable Louisiana rainstorms, which he described thus: “In Louisiana, the rain falls in nine-foot cubes, with little air-holes in between.” We experienced some “cubes” down there, and he was right. We were thankful that the storms were usually brief. (An Earl Long story: After being elected Governor based on his promise of “No New Taxes,” Long went to the legislature and introduced no fewer than twenty (20) new taxes. The legislature dutifully and quickly passed them all, and afterwards Earl was besieged by reporters. One particularly loud reporter bellowed out, “What about your promise of no new taxes?” Walking quickly out the door, Long shouted back, “I lied.”
I think that Long introduced what was called a ‘tax on Lying’- actually a tax on newspaper revenue. Doesnt make sense he promised no new taxes, as by modern standards he was to the left of Bernie Sanders, but that was a popular place for a politician in dirt poor Louisiana during the depression
It has been raining persistently in this region for several weeks. Prior to that, this region had been suffering drought conditions.
Plus, the recent persistent rains have been accompanied by equally persistent and unusually strong and long lived onshore winds.
It was not simply the short term one, or two, or even five day rain totals. It was the combined effect of each of these factors that added up to cause the massive flooding.
Additionally, the concentrated rainfall over a large portion of the individual watersheds involved are contributory. One foot of rain over one county in an hour may not have the result of the same amount over twenty counties, that all happen to drain the same basin or basins. And saturated ground with no ability to absorb falling rain has a huge contribution to flooding, as do onshore winds which hinder stream flow out of the estuaries of the flooding rivers.
Also, I think it was the flooding, or the stream flow, and not the rainfall totals, that are usually referred to as 100 year or 1000 year events.
I have thought for years that the actuarial charts, or whatever statistical means are used to ascertain the historical frequency of such events seems to need some revisions.
It seems that both on the low and the high end, such extreme events may not follow so-called Gaussian (if that is the correct term) statistical correlations. I am by no means an expert on statistical matters (perhaps not on any other matters either…just opinionated), but perhaps this is one of the instances where such events are correlated, such that whatever leads to them happening once may predispose them to occur again in close chronological proximity to the initial event.
Stalled out weather systems, stuck tropical storms or cut off lows, and atmospheric rivers which seem at times to be trying to establish a semi-permanency on certain occasions, all lead to extreme rainfall totals which appear to be a mechanism apart from regular run-of-the-mill weather events.
On a related but totally separate train of thought, I have wondered if some such semi-permanent weather system may be responsible for the rapid onset and/or termination of glacial/interglacial cycles.
Imagine a weather system setting up in winter that becomes “stuck” over a certain area, such as Hudson bay, for an entire winter. Could such an event result in such a tremendous amount of moisture being deposited as snow that it could become a self perpetuating phenomenon, and lead to an ice age all by itself?
Far fetched I know, but I have not heard any credible explanations for such rapid onsets or/and terminations…just thought I would toss it out there and see if anyone wants to pick up the ball and run with it.
The old wives’ tales that “disasters come in clumps of twos and threes” is the common man’s observation of the Poisson Distribution.
Flood peaks (or extreme rainfall for that matter) usually follow a probability distribution with a heavy tali and a high skew such as the log-normal, log Pearson Type 2, etc..
Menicholas says: “perhaps this is one of the instances where such events are correlated, such that whatever leads to them happening once may predispose them to occur again”
Right on! If you set up a fat “pineapple express” into California, or a good Gulf Coast/Hatteras cyclogenesis and intensification pattern, Bivalve, NJ, can get repeated northeasters.
Out here in Colorado it el Nino, of course. 90% of my 4-foot snows come in the one year in five that’s el Nino. So if there’s one of those storms, it’s likely el Nino, and the odds of another one have gone up.
That 6-foot snow I mentioned was el Nino.
Menicholas also says: “Imagine a weather system setting up in winter that becomes “stuck” over a certain area, such as Hudson bay, for an entire winter.” Back in my thesis days (looking at ice age precursors in Baffin Island), that was the “Snow Blitz” theory, proposed by some Brits, I think. So rather than an inexorable cooling thanks to the earth’s tilt and orbit, this suggests a real outlier – a one in 100,000 year event – covers the cap with snow, reflecting sunlight all summer to keep the snow there, and it builds up over the winter, reflects more sunlight the next summer, and so on. The appeal of this is that since as far as we can tell, weather beyond next week is essentially random. So why should climate, which is the statistical aggregate of all weather, be any less random?
In my Weather & Climate class I modeled a century of US climate quite nicely by rolling dice. It even got the PDO, dust bowl, and 1998 el Nino right, with 1934 scoring 12 on the die. I got in trouble with the university warmers, who rely on federal grants for more expensive models that don’t work, for that one.
Richard K
Your comment/prediction: –
” The appeal of this is that since as far as we can tell, weather beyond next week is essentially random.”
is exactly what you and I and thousands others have been tryIng to say.
Certainly about the UK – England has weather . . . . . . . .
Guessing about three weeks ahead is – essentially – GUESSING – at least in the UK, and other areas with a link . . . .
Brgds
Auto
– by Bby
Wiki to the rescue..
Greatest 24-Hour Rainfall[5][6][7] 17.00 inches (432 mm) August 27, 1995 Antreville Abbeville
https://en.wikipedia.org/wiki/List_of_South_Carolina_weather_records
Over 30 inches of rain fell overnight in Nelson County Virginia in 1969 from the combo of Hurricane Camille and upslope flow. One in a thousand? You bet. Maybe more.
“Once in a thousand years” makes me think SC was overdue.
The only thing on steroids in the world of Mann is stupid.
Did anyone predict this rain event?…and by ‘predict’ I mean say it was coming before it started!
Yes. Saw it on the weather news before it happened. REX block identified by the meteorologists. They were pretty much spot on though they said the exact amount of rainfall was indeterminate. I thought they did an excellent job of warning what was coming but who ever listens?
Yes!
The computer models that failed to accurately predict where and when the hurricane would go, had forsen this extreme rain event well in advance.
Too bad they do not spend more time and money trying to predict what will happen to the rivers and streams in an area if the predicted rains do indeed materialize.
I did not hear the weather guys saying they would get 12-24 inches of rain also telling people in zones A, B, or C, to start packing up valuables, moving expensive crap onto shelves, and getting the heck out of the affected areas if they could.
What you hear in Florida? The temperature of the ocean dropped.
This morning on “The Storm Channel” they explained that a “500 year” or a “1000 year” flood doesn’t mean that they only occur once in that many years but that there is a 1 in 500 or 1 in 1000 chance that they will occur at all.
I’m not a meteorologist so I don’t know if that’s true or not.
If true, the nomenclature should be changed.
If not, shouldn’t they be saying the chances are lower?
But I still get the feeling they would have preferred to report that a hurricane had hit Manhattan.
PS What SC flood records exist from 1015?
That is if CAGW is “settled science”.
That is a statistical computation, from what they already know hadn’t happened. That tells exactly nothing about what might happen from now on. Statistics is not predictive; it simply mutilates, the known data in the already known data set, to produce numbers that statisticians have a name for, but adds no knowledge to what is already recorded in the data set.
I’ve done hydrology designing dams, bridges, etc. although I didn’t look at the exact rainfall records for this storm someone mentioned 10 inches in a day……this shouldn’t even be close to a 100 yr event…..it depends on the area…..but 100 yr events are about 20 to 25 inch rainfalls in 24 hours. I’m thinking SC would be at the higher end of that range.
Rainfall nomographs. Standard engineering storm water management. So yeah, you could get a 1/1000 event one year and a 1/1500 year event the next but highly improbable though possible to have several unlikely events in a row due th the atmospheric conditions.
Gunga Din
Ah none. Worst yet, proxies may be iffy for the Charleston area. Was a bit of a war there 1861-1865. Siege guns, trench warfare. A precursor to the first world war. Also the city being burned down. Everything is probably jumbled about, so making a call that there is evidence of a storm from 1015 who knows. Parrot and Dahlgren Guns may have left a few stones and clumps of dirt unturned
michael 🙂
PS yes I’m a N.E. Yankee
Here in our local Canadian city we design storm sewers to 100 yr return storms…..as calculated from a whopping 35 years of rainfall records.
Then I suggest you move in the next 65 years to …uh… somewhere else.
Dave: the 1/100 return period is normally for “overland” flow. The sewers are often only designed for 5 to 25 years depending on the city bylaws. In other words, streets are expected to flood in 1/100 year events. Eg – City of Edmonton, Alberta standards;
Ponding Depths: The minor system should be designed such that the depth of ponding in the street does not exceed 0.15 metres in a 1 in 5 year rainfall event. The major system should be designed to limit the depth of ponding in the street to 0.35 metres in a 1 in 100 year rainfall event.
And that is why I have always bought on high spots.
“And that is why I have always bought on high spots.”
Smart man.
If one does not use one’s education to make important decisions…
It seems like some people forget everything they know when making housing decisions, and just concentrate on emotions…like, “Look at that river view!”
Re “high spots”: It was my final determining criteria when I decided between the five houses I had decided on as being suitable.
Not my first choice interior of house wise, but top of the list in terms of storm resistance and flood resistance (Cement tile roof, roll up storm shutters, cement block construction, hip roof structure, house on raised slab and top of a bluff on yellow sand subsoil, two major canals within two blocks.)
An aside.
I doubt that many (if not all) of those commenting on this are indifferent to those effected by the flooding.
It’s the “Man-caused-weather” most are addressing.
A 1 in 1000 year event.
The earth is 4,500,000,000 years old. So that means that only 4,500,000 similar events have happened.
How rare is something that has happened over 4 million times?
Every ten centuries rare?
Similar levels of rain occur much more often than one in a thousand years, we had more rain where I live from Floyd in IIRC 1999, NC had a really big rainfall in 1916 near Ashville, a few years back Coca Beach had 30 inches over a day or two. That any particular place would have a big event is probably pretty rare but there are lots of places.
Hurricane Fay inundated Cocoa Beach area back in 2008. 20 to 30 inches of rain…..
http://ireport.cnn.com/docs/DOC-63691
“Flooding in Brevard County Florida, City of Cocoa
Thursday morning 8/21/08
Holding stationary over the northeastern part of Florida for hours, Fay dumped rains of 50 to 75 centimeters (20 to 30 inches) in some parts of the state, and caused widespread flooding.”
I had a very bust work month, and to replace a bunch of equipment that was flooded out during Fay.
There were many communities in Melbourne and nearby locales that were built on ponds and lakes with inadequate weirs to allow the ponds to flow over into the adjacent canals.
One community right next to I-95 flooded when the weirs became clogged with turtles. They would have had no problem at all, but the hydrostatic pressure was such that, once all those turtles had either been flushed or swam with the current into the weirs, they could not get back out, drowned, and there were enough of them to fill up and clog the entire weir.
Crazy.
Properly planned and engineered, but who’d’a thunk of it with those turtles?
(For those unaware, Florida has large soft shell turtles that can be 16 inches or more in diameter, and these inhabit some ponds in large numbers. I think they are a main food source for alligators and otters in many locations.)
Sorry, …a very busy work month, and had to…
From a local PBS station website:
*****
Many Arizonans shared one unique collective memory of the ’70s. No, it wasn’t 8-track tapes, Farrah Fawcett’s hair, nor even the CB radio craze. It was…the floods! Dams store water in reservoirs for use during drier months. Sudden, excessive rainfall can fill the reservoirs and water must be released…sometimes lots of water. And in Arizona in the ’70s, there was a lot of sudden, excessive rainfall. In the first half of the decade, three powerful storms hit Arizona killing over 30 people and destroying or damaging nearly a thousand homes.
Between October 1977 and February 1980, there were seven floods. Phoenix was declared a disaster area three times and 18 people lost their lives.
“It was terrifying, and that was the time that the helicopter reporting really came into the forefront in television news. Jerry Foster flying over and showing the flash flooding, and the cars and the cactus going down the river.”
Mary Jo West, broadcast journalist
“How many 100-year floods did we have in the ’70s? It seemed to me we had one everyother Tuesday. I first got here and I had to cover one of them. They kept saying, ‘This is a hundred-year flood.’ And I said, ‘What does that mean? They said, “This is the severity of a flood that will only happen once in a hundred years.”
Jana Boomersbach, journalist
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Yep, I lived through all of them. It’s been one of those very wet years yet again – and looks like it will continue well into the winter months. Some days I feel like Methuselah…
These may be 1 in a thousand rate for a single area, but with hundreds of similar sized areas over the surface of the earth, I suppose we get 1 in 1000 events SOMEWHERE on earth every 10 years or so.
The trick is that for any one point, it might be a 1000 year event, but there are thousands of points, so such an event somewhere is LIKELY.
September, 1989 rainfall from Hugo:
Edisto Island, SC – 10.28
Mount Pleasant, SC – 8.10
Rainfall in Charleston this month has been very heavy, but not unprecedented.
The is not a ‘complex meteorological event.’ It is a simple event. A low here, a high there, and a hurricane feeding into the nip. There, I described it in 13 words.
The unusual thing s the unwavering nature of the flow. Typically such flows will move after a day or three.
True, but that is not complexity.
I see Mr Mann, it is an already extreme meteorological event, but now according to your exacting scientific verisimilitude, it is a worser extreme. Alfred E Newman would be proud.
Traveling further down the poop chute of climate change, Doesn’t 1 in a thousand year rainfall claim undermine the anthropogenic CO2 argument since there is no evidence anthropogenic CO2 shows up every thousand years to create extreme rainfall? Mr Mann, Mr Mann, could you answer?
Thanks, Anthony.
http://www.ssd.noaa.gov/goes/east/eaus/flash-wv.html has been a good window into this “atmospheric river” weather event.
Once in a thousand years? HA!
http://www.erh.noaa.gov/akq/Hur30s.htm
michael
There the Climate Liars go again; confusing weather with climate. And the low-information, low-IQ Believers will lap it up.
Where’s his proof? Some “scientist.” Please quantify for us what the storm should’ve brought if climate change hadn’t worsened it.
POS is like Al Gore, always hoping for the next devastating storm to use for his activist agenda. I wonder which circle of hell he’ll be on?
Look at east coast hurricanes in 50’s as well
John, how about these instead, a good list to put things in perspective
http://abcnews.go.com/Technology/story?id=97045&page=1
michael
But isn’t it more fun to “chicken little” this event, especially with the pending Paris meeting?
USA Today/CNN Weather is saying this is the 6th 1,000-yr event in the US since 2010.
What they don’t tell you is that there can be a 1,000-yr rain event over 1-hr. Or 2-hrs. Or 10-hrs. Or 24-hrs. Or 48 hrs. Or 72-hrs. Or any amount of time. So 1,000-yr events happen on average much more often than once every thousand years.
Doesn’t work like that. These events are hydrology terms used for the design. The basic events are 1 hr 10 yr storm used the design of small drainage areas. Like the channel running through your development. There’s a term called time to peak (Time to achieve maximum discharge)which establishes what storm to use. The other is a 24 hr 100 yr storm. (Used for larger drainage areas like rivers) Just those two for permanent structures. Temporary structures like a coffer dam would be desiged for less.
We only have about 140 yrs of rainfall records. So we don’t even know what a 500 yr event would be. basically they’re just guesses. And pretty useless also….we don’t build things to last 500 yrs.
Yes, it does work like that. You can have an intense 1,000 yr, 1 hr storm event in Dallas, TX one day and then a prolonged 1,000 yr, 72 hr storm on another. Or you can have 1,000yr storms of the same duration (or different) in different parts of the US. Both are 1,000 yr events, and both might actually only happen once in 1,000 yrs. Yes, they are hydrology terms used for design…but are you trying to argue that a 24hr, 100yr storm is not an estimate of rainfall over 24hrs with a return period of 100yrs (call it 1/100 chance of happening every year, or likely to happen 1 out of 100 yrs)? Those time periods are not just made-up.
There are a bevy of design storms, both in total rainfall and in rainfall pattern. It depends on location. And yeah, we are just guessing to what the 500-yr storm is. But we have statistical methods to estimate it.
the question is are those methods giving an accurate measure of reoccurrence?
Mostly comments (in the news) from people that don’t know anything about statistics.
If this was a once in a thousand year event that is just the estimated probability is 1/1000 based on current understanding of the conditions there. And lots of places around the world experience once in a thousand years events every year (remember many many thousands of places).
At least one report quoted (I think) the governor as saying most rainfall in 1000 years. Which is just some mis-understanding.
What would be news is a report that says we would have thought was a thousand year event but based on changed conditions (presumably AGW) we now think this will be a one hundred year event. 🙂
That’s not correct…..a design storm is defined as the maximum amount of rainfall with a certain period. It’s not a 1 in 1000 chance of it occurring. It’s pretty common to have this event….it has to do with storm isoheytals. And how they align with drainage areas. For instance in a 10 year storm. You might have that often. Because the atmosphere is limited on how moisture it can hold. Maximum short intensity storms can happen often. Usually a heavy thunderstorm will do this.
No, it is correct. Don’t take my word for it…take it from the USGS or any stormwater textbook. http://water.usgs.gov/edu/100yearflood.html
‘…This question points out the importance of proper terminology. The term “100-year flood” is used in an attempt to simplify the definition of a flood that statistically has a 1-percent chance of occurring in any given year. Likewise, the term “100-year storm” is used to define a rainfall event that statistically has this same 1-percent chance of occurring. In other words, over the course of 1 million years, these events would be expected to occur 10,000 times. But, just because it rained 10 inches in one day last year doesn’t mean it can’t rain 10 inches in one day again this year…’
“1-percent change of occurring in any given year” = “estimated probability 1/1000”
If it was a 1,000 yr rainfall event somewhere in SC, then it was improper that no duration was given. But a 1,000 yr event has a 1/1,000 chance of happening in a given year (based on what rainfall data we do have and the statistical methods behind interpolating and extrapolating them to other return periods).
Yes, you might have a 10-yr storm often, since the terminology implies you have a 10% chance of seeing one in a given year. And yes, maximum short intensity storms can happen often. A 10-yr storm need not just be short, though. It can be associated with a 24 hr or 72 hr duration though…which isn’t a short intense storm. Similarly, a 1,000 yr storm can be associated with a 1 hr intensity as well.
You seem to have some idea about what you’re talking about, but you’re not getting it right.