Pakistan floods last summer could have been predicted

Peter Webster at Georgia Tech is a colleague of Dr. Judith Curry.

Data generated by the European Centre for Medium-Range Weather Forecasting (ECMWF) in late July 2010 indicated imminent, extreme precipitation over Pakistan. Click here to see ECMWF Extreme Forecast Index maps and the centre’s newsletter article on rainfall predictions prior to the floods.

AGU Release No. 11–04

31 January 2011

For Immediate Release

WASHINGTON—Five days before intense monsoonal deluges unleashed vast floods across Pakistan last July, computer models at a European weather-forecasting center were giving clear indications that the downpours were imminent. Now, a new scientific study that retrospectively examines the raw data from these computer models, has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand.

The study also finds that the floods themselves could have been predicted if this data, which originated from the European Centre for Medium-Range Weather Forecasting (ECMWF), had been processed and fed into a hydrological model, which takes terrain into account.

The July floods killed thousands of people and tens of thousands of cattle, and left large parts of Pakistan in shambles. The waters displaced, or disrupted the lives of, an estimated 20 million people.

“People don’t understand the powers of modern environmental prediction,” says Peter Webster, a professor of earth and atmospheric science at the Georgia Institute of Technology in Atlanta and lead author of the new study. “This disaster could have been minimized and even the flooding could have been minimized. If we were working with Pakistan, they would have known 8 to 10 days in advance that the floods were coming.”

He and his colleagues report their findings in a paper accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The ECMWF, a London-based organization of 33 participating European countries, “does not give out weather forecasts and weather warnings to the general public or media,” notes ECMWF scientist Anna Ghelli. “ECMWF provides numerical forecasts to its member and co-operating states and they are responsible to prepare forecasts for the public and advise the authorities in their own countries.”

“We noticed that the signal was there five days in advance,” Ghelli recalls. However, the lack of a cooperating agreement between the forecasting center and Pakistan meant that these rainfall warnings didn’t make it to the Pakistani people, nor did Pakistan’s own meteorological agency forecast the flooding.

In their research, the Georgia Tech meteorologists use data from the European center to analyze whether or not the rainfall was above average for Pakistan and if the huge surges in the Indus River would have been predictable if flood forecasters were monitoring the country. They determine that, while the rainfall total for 2010 was slightly above average for the region, the July deluges were exceptionally rare, with rainfall amounts exceeding 10 times the average daily monsoon rainfall. They also find that if a flood forecasting model had been in place, the floods would have been predicted in time to issue warnings.

As a result of processing the raw output from ECMWF models from before the Pakistani deluge, the team achieves greater accuracy than the raw numerical forecasts alone provided. Some weather stations in Pakistan recorded nearly a foot (30 centimeters) of rainfall during the 4-day downpour. The after-the-fact predictions by Webster and his colleagues came in slightly below those amounts at the same locations.

Webster says that processing raw data into weather forecasts and combining them with hydrological models is only half the work. In order to have any effect, the resulting flood forecasts must be successfully disseminated at the village level, and local leaders must also understand them.

In nearby Bangladesh, Webster spent five years creating a flood-forecasting technique and organizing a cooperating agreement with the Georgia Institute of Technology, ECMWF, the Asian Disaster Preparedness Center and the government of Bangladesh. When flooding occurred there several years ago, warnings made possible by the forecasting pact not only averted loss of life, but also saved residents as much as $450 per farm — about the equivalent of an average annual salary in that country.

In a few weeks, Webster will attend an international meeting of developing nations in Bangkok to build support for flood forecasting in Pakistan. He says a forecasting system in Pakistan would cost a few million dollars to set-up, but as little as $100,000 a year once operational. He hopes to convince the World Bank, currently providing $1 billion of flood-recovery financing to Pakistan, to fund the project.

In Bangladesh, Webster recalls, an imam at a local mosque told him about how they discussed the flood forecasts each day in prayer. This is the sort of local solution that Webster envisions for Pakistan as well.

The National Science Foundation funded this research.

Notes for Journalists

As of the date of this press release, the paper by Webster et al. is still “in press” (i.e. not yet published). Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this paper.

Or, you may order a copy of the paper by emailing your request to Peter Weiss at pweiss@agu.org or Maria-José Viñas (mjvinas@agu.org). Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release are under embargo.

Title

“Were the 2010 Pakistan floods predictable?”

Authors

Peter J. Webster, V.E. Toma and H-M Kim: School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia.

Data generated by the European Centre for Medium-Range Weather Forecasting (ECMWF) in late July 2010 indicated imminent, extreme precipitation over Pakistan. Click here to see ECMWF Extreme Forecast Index maps and the centre’s newsletter article on rainfall predictions prior to the floods.

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54 thoughts on “Pakistan floods last summer could have been predicted

  1. I think this is interesting and a real way in which modelling can be applied: short term predictions.
    There are two facets required for such models to be useful. The first is a high probability of detecting an event when it is likely to occur. The second is a low false alarm rate. If the false alarm rate is too high, the forecast is useless.
    I hope Dr Webster addresses these issues in the paper. I look forward to reading it.

  2. “Now, a new scientific study that retrospectively examines”
    =================================================
    The best hind-casters money can buy………..
    Not a one of them could predict anything if their lives depended on it.

  3. You don’t think the U.S. is not in for some big flooding come spring?
    Quite the pile of precipitation on the ground!

  4. So all this money being wasted on looking for evidence of possible climate change that might cause loss of life, is more important than using existing technology to predict actual severe weather that really does cause loss of life.

  5. Being a former weather forecaster I take papers like this with a bit of skepticism. The otherside of the coin is how many times have the forecast models been wrong? Being right a few times does not make a case (even if the models forecast a record weather event). One of the old rules of thumb forecasters used is never forecast a record event -especially past the H+24 period. If one does forecast a record event (temp, thunderstorms, etc…) you had better have solid meteorlogical reasoning other than what the models “say”.

  6. It is one thing to make an accurate prediction but to suggest that they (Pakistan) could have controlled the flooding with 8-10 days notice is the height of lunacy. Pray tell how could they have diverted or stored the water to avoid this problem.

  7. With Pakistans infrastructure I doubt 5 days extra warning would have made much difference, as it was the biggest critisism was for the civil Govt who just stood by, nothing got done until the army got involved.

  8. “The July floods killed thousands of people and tens of thousands of cattle, and left large parts of Pakistan in shambles. The waters displaced, or disrupted the lives of, an estimated 20 million people.” Warnings and preparation were possible due to accurate computer models.
    What great possibilities there are for “computer models” if they are used for scientific purposes which are then used to inform or warn people/societies. What monstrous possibilities there are when they are used to disinform and control people/societies.

  9. Peter Webster says, based on information he got from ECMWF, that he could have told them 8-10 days in advance.
    “We noticed that the signal was there five days in advance,” Ghelli with the ECMWF, says the signal was there five days in advance.
    Peter is blowing smoke…………..
    If he “could have” predicted it, why didn’t he?
    Because he can’t………………

  10. Given the death toll and hardship endured, this is bound to be inflamatory.
    Even if such detailed forecasts were possible with sufficient certainty so as to warrant action, the underlying issue is the extent of reaction possible with just 5 or 8 or even 10 days prior notice. Given the infrastructure, it would seem to be a herculean task to evacuate the locals from that area. Certainly the deploymengt of effective flood defences and diversions would not have been possible on this time scale. It is probable that little mitigation would have been possible in the circumstances.
    On a similar vein, there are similar issues over the Queensland floods. Some are saying that these were predicted 6 months in advance and in any event City planners had been ignoring flood issues as from the late 70s. There may well be a case that far more could have been done to mitigate the effects of those floods.

  11. But, but by saving human lives and property you put even more burden on Mother Earth. It is surely an evil plot, this flood forecast thing, irresponsible interference with Holy Gaia’s self-defense.
    /bitter sarc off

  12. “Now, a new scientific study that retrospectively examines the raw data from these computer models, has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand.”
    Yea, but that’s not anyones job. Their job is convince the populas that we are all doomed from CO2. Its a full-time job and there is not time for anything else. Besides forecasting something 10 days out will not get you a research grant.

  13. A little bit late to the show aren’t they?
    Here is a prediction that is just is accurate….
    A category 5 Hurricane will hit the Gulf Coast in 1969. It’s gonna be nasty, so get prepared.

  14. Hindsight is 20/20. I am not impressed.
    And how many similar computer driven predictions of catastrophe did NOT occur?
    Cherry picking a possibly correct forecast after the fact is NOT science unless you include all data to show how many times you were right, versus how many times you were wrong.

  15. Astrologer to prospective client: “I see you were born under a water sign, Pisces, and hence you are drawn to water. That’s why you married a Navy man. I could have predicted it!”. These kind of successful retroactive “predictions”, based upon computer simulation, are an old joke in the computer modeling field. Successful retroactive predictions are a dime a dozen. It’s really a modern “high-tech” variation on an ages old parlor trick. What is exceedingly rare are successful forward predictions.

  16. I have some concerns here. The ECMWF is one of the best models and they are saying it predicted the precipitation up to 8 days out. That’s fine from a meteorologist perspective and easy to say in hindsight, but it’s a much more complex issue when it comes to real world implementation of this knowledge.
    Let’s just say 5 days as one quote in this article said. What could have been done 5 days in advance to mitigate impact and how much would it have cost compared to what could have been saved? How often would actions like this need to be taken if the 5 day forecast was taken as verbatim? How often would those actions be right, wrong, and whatever shade between those two that can occur? How much would that cost and would spending money on 5 day forecasts protect enough property and save enough lives to be worth it over the long term?
    My gut feeling is that 5 days forecasts can’t be used for all that much without wasting more resources in the long run than it would actually protect.

  17. When I was a teenager, I used to go to the horse races with my mother. At one of those meets, a rather long shot won a race, and paid a ton of money. After the race, I told me mother; I was going to tell you to bet on that horse.
    So Obama tells us we have the technology to get 80% of our energy from clean green free renewable sources.
    So now we are told that the Pakistan floods could have been predicted.
    Well it’s pretty obvious to me that they couldn’t have been predicted, because they weren’t. And when we get, and have systems in place that can predict such things they will get predicted.

  18. So they already collect the data necessary to predict massive floods days in advance and they have the necessary computer models to process that data and make accurate predictions.
    And for just a million dollars more and a few hundred thousand per year…

  19. Gee you see storm brewing that will drop a foot of rain on you neighbor and because he doesn’t belong to the group you just buy popcorn and get a ring side seat. I’d be too embarrassed to then go publish a paper about it.

  20. That information was worthless as it wasn’t available to the people that needed it.
    This information was created with public funds and only available on a need to know basis. The people involved are now patting themselves on the back on their genius, to bad it was wasted. pg

  21. chemman says:
    February 1, 2011 at 6:28 am
    It is one thing to make an accurate prediction but to suggest that they (Pakistan) could have controlled the flooding with 8-10 days notice is the height of lunacy. Pray tell how could they have diverted or stored the water to avoid this problem.
    #####
    You should spend as much time reading papers and news as you do shooting your mouth off. it would add to the conversation.
    For example, 15 seconds of search yielded this.
    “Similarly, local accounts and media reports suggest that the barrage staff has failed to properly operate the newly installed motorised hoisting system.
    According to these reports, 10 gates were not fully opened which, if true, turned out to be the main cause of the flood disaster. ”
    And of course evacuation prior to the flood would have helped the matter.
    Looking at the charts Peter showed me in Lisbon it was even possible to take actions before 10 days out.

  22. latitude says:
    February 1, 2011 at 6:47 am
    Peter Webster says, based on information he got from ECMWF, that he could have told them 8-10 days in advance.
    “We noticed that the signal was there five days in advance,” Ghelli with the ECMWF, says the signal was there five days in advance.
    Peter is blowing smoke…………..
    If he “could have” predicted it, why didn’t he?
    Because he can’t………………
    ##################
    did you even take time to read the paper or understand the methods.
    Peter is able to request data from ECMWF .
    He then takes that data and feeds it into a hydrology model.
    That’s the innovation.
    The people who run ECMWF do not feed precipitation into a hydrology model.
    But they do provide raw data to Webster. What Webster did was take that data and
    drive a local hydrology model with it.
    RyanMaue: Georgia Tech purchases the ECMWF grids — you can do it yourself if you have a couple hundred thousand dollars. This paper at AMS is along the same lines: taking the ECMWF grids and post-processing them. It is not novel, but it can provide great societal benefit (if done right). http://ams.confex.com/ams/91Annual/webprogram/Paper186495.html

  23. This sounds more like the MET nonsense. Go back in time and micro-analyze your own model to verify you were brilliant. …..But forgot to tell anyone.
    The fact is that the rain was forecast. The stable high pressure area over Russia moved the jet stream and a mass of moisture over Pakistan. These clouds would have been plainly visible. Extreme deforestation, dangerous building, lack of maintenance, lack of flood control, and the general incompetence of Pakistani officials did the rest.

  24. This paper is actually an admission that the CO2 obsessions of climate science cost people’s lives.
    If they were focusing on what is actually happening, instead of lucratively selling hype and fear they could actually be helping people.

  25. #
    #
    Golf Charley says:
    February 1, 2011 at 5:57 am
    So all this money being wasted on looking for evidence of possible climate change that might cause loss of life, is more important than using existing technology to predict actual severe weather that really does cause loss of life.
    #########
    Yup. But some of the readers here are so intent on criticizing everyone in the field of climate science that they raise objections without thinking or reading. For example, Webster is very interested in the question of natural variability and thinks we havent devoted enough attention to it. So there you have it. A climate scientist who
    1. Wrote some critical things about trenberth on Judith Curry’s blog.
    2. Thinks that natural variability needs more study ( especially the 1930-1940 event)
    3. Finds a practical use for GCM outputs.
    And readers on WUWT who havent even familiarized themselves with the basics spout off whatever negative nonsense comes to mind.
    And people wonder why those in climate science who SHARE some of your concerns hesitate to show up and discuss things

  26. Steve Mosher,
    I see your point about knee-jerk criticism (mine wasn’t of that nature: if you can see it coming tell your neighbor even if they don’t belong to the club). However, you are by inference accepting that the deluge was not a forecast but a certainty. I would like to see 100 case histories of such a lining up of ducks and see how many drastic storms followed in the target area: more than 25% would even be useful. This type of probability should be part of this paper or it creates a wrong impression a la Met Office regarding the reliability of forecasts and becomes a look-how-smart-we-are paper.

  27. Regardless of the methods, they have to be able to predict this kind of stuff with regularity to obtain general credibility. When that happens people will pay them for their services…on the commercial market.

  28. Thanks for the comments. But perhaps you should read the paper before voicing your prejudices from behind pseudonyms.
    After the devastating floods in 1998 when 60% of Bangladesh was inundated for 3 months, we were asked by USAID if the floods were predictable. We carried out the same exercise that we did for the 2010 Pakistan floods and showed that there was predictability. Over the next decade, using as a base of ECMWF forecasts we developed a real time flood forecasting and warning system for Bangladesh. In 2007 it became operational (read “real time”) with 10 day (later 15-day) forecasts made each day to provide probabilities of floods. During 2007 and 2008 we conducted pilot studied in which unions were trained to to interpret our probabilistic forecasts and take preparatory actions. There were three periods of flooding along the Brahmaputra each of which was forecast with no false positives either along the Brahmaputra or the Ganges. People were evacuated and for the first time in the history of Bangladesh floods were anticipated and actions taken.
    If you would like you can read our paper in the November issue of the Bulletin of the American Meteorological Society. You can download the paper at:
    http://journals.ametsoc.org/toc/bams/91/11
    But I doubt few of you will bother. Other things, as many of you have demonstrated, are far easier!
    The point of all this is that the Pakistan paper followed our “tried and true” system of determining if there is predicability before setting up a hydrological prediction system. I think this is a honest way of doing science and, at the same time, doing some good
    Peter Webster

  29. Well, everything’s predictable. With a probability between 0 and 1. That would be 110% if you’re a hockey player.

  30. According to the press release: “Now, a new scientific study …. has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand…. [and] … the floods themselves could have been predicted if this data … had been processed and fed into a hydrological model, which takes terrain into account.”
    In other words….
    Our hindcasting has proven that if [someone] woulda, shoulda, coulda selected the correct data [from the infinite universe of selectable data] then [some type of] proper computer model woulda, shoulda, coulda pre-casted the events that we can now see are easily and obviously hindcasted.
    Oh yes, can we have some more gigamoney and some faster petabyte disk arrays please?

  31. Garry says:
    February 1, 2011 at 11:12 am
    According to the press release: “Now, a new scientific study …. has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand…. [and] … the floods themselves could have been predicted if this data … had been processed and fed into a hydrological model, which takes terrain into account.”
    In other words….
    Our hindcasting has proven that if [someone] woulda, shoulda, coulda selected the correct data [from the infinite universe of selectable data] then [some type of] proper computer model woulda, shoulda, coulda pre-casted the events that we can now see are easily and obviously hindcasted.
    Oh yes, can we have some more gigamoney and some faster petabyte disk arrays please?
    #####
    wrong. According to my conversation with Webster this is how it is done. There are essentially 51 forecasts that are done every day.
    The first forecast is a high resolution deterministic forecast. You put in initial conditions as best you know them and then run the model. This answer is almost always wrong. Then you run 50 different versions at a lower resolution perturbing
    the initial conditions. These 51 form an ensemble and from the ensemble you construct probability maps for things like wind temperature and precipitation.
    What Webster did was take these output of the model say 15 days prior to the floods.
    He then fed the predictions for precipitation into a local hydrology model complete with terrain. That allows him to calculate a probablity of flooding 15 days in advance, 14 days, 13 days, etc. At day 10 ( recaling from our conversation) the probability of a flood broke 80%.
    So this is not about selecting data from an infinite universe of data. Its about using the data output from one model to drive another model.
    Basically your weather model predicted 10-30 buckets of water would fall.
    if you put 10-30 buckets of water into a hydrology model, it predicts a flood.
    That’s an interesting result. Of course you ant to test for false alarm rates and detection rates, but it is better than what governments do now:
    Now they tell citizens to worry, work, and wait

  32. RyanMaue: Georgia Tech purchases the ECMWF grids — you can do it yourself if you have a couple hundred thousand dollars. This paper at AMS is along the same lines: taking the ECMWF grids and post-processing them. It is not novel
    ####
    Noted, it seemed novel to me, particularly in the statistical approach peter used, but I could be wrong,

  33. @ Peter Webster,
    “…But I doubt few of you will bother. Other things, as many of you have demonstrated, are far easier!
    The point of all this is that the Pakistan paper followed our “tried and true” system of determining if there is predicability before setting up a hydrological prediction system. I think this is a honest way of doing science and, at the same time, doing some good”
    ————————
    I’m sure you meant “I doubt many of you will bother…” and you’re right, of course.
    I sympathize with your sense of being unappreciated, but your swipes at commenters who are not kindly disposed toward your position are a case of “Asinus asellum culpat”.
    Previously formed opinions are only prejudices to those that don’t share them.
    As there are more things to investigate than there is time to do it, I offer “the donkey blames the jackass” for the Latin, above. It’s a variation on pots and kettles. I had to look it up.
    I have taken a cursory look at your paper, I will try to give it more time.

  34. “..raw data from these computer models”? The output of computer models is not data, raw or otherwise.

  35. Maxbert says:
    February 1, 2011 at 12:29 pm
    “..raw data from these computer models”? The output of computer models is not data, raw or otherwise.
    #####
    obtuse. call it the level 0 data. But if you want to be pendantic there is no raw data ever. All data is processed.

  36. Peter Webster.
    On reading your paper I note that the upstream data from India is not made available to Bangladesh and you later imply that this data could be used to predict flooding. Why not just get this data?

  37. ECMWF seems to be a good model but it is pretty useless as hardly anybody can get the data unless you pay it twice over. We already finance it with our taxes here in Europe (40 million euro a year) but we can not get the results without paying a fortune on top. I rather put my taxes to improve the GFS.
    As four 5 days warning, that would be plenty in developed countries but would make hardly any difference in Pakistan poor regions.

  38. Peter Webster,
    Further to my earlier comment you identified two main times for possible flooding, melting snow in early spring and then later the monsoons.
    How far in advance do you think it is feasible to predict a flood while a monsoon is ongoing? To me the snow melt flood would be more predictable.
    Nice paper.

  39. Peter Webster says:
    February 1, 2011 at 10:13 am
    Kudos to you for coming here and clarifying your methodology. As you outline it, it looks like it could be a very useful tool in the future for saving lives and lessening the disruption to people’s lives and I do hope it will be widely adopted.
    That said, I can understand the sentiments of the other posters. People have been lied to repeatedly over the last decades by people who call themselves scientists, and they’re angry. It is part of a backlash where unfortunately, even the good people get trampled underfoot. Just as a matter of interest, have you included access to your data and methodology along with your paper?

  40. steven mosher says:
    February 1, 2011 at 12:57 pm
    Maxbert says:
    February 1, 2011 at 12:29 pm
    “..raw data from these computer models”? The output of computer models is not data, raw or otherwise.
    #####
    obtuse. call it the level 0 data. But if you want to be pendantic there is no raw data ever. All data is processed.
    _____________________
    At the risk of further insults, I stand by my statement. Webster defines data as “factual information (e.g. measurements or statistics)” In engineering we define it that way too. Models, including computerized ones, depend on assumptions to produce estimated values, linearizations, projections, predictions, etc. This output is can be useful, but should never be confused with real-world data.
    Measurement data, furthermore, are NOT always processed; sometimes they’re merely recorded. (You can call that processing “if you want to be pendantic. [sic]”) The temperature outside the house right now, for instance, needs no processing– unless, of course, you’re Jim Hansen.

  41. I was among the earliest commenters. When I read other comments, from people I greatly respect, I thought I was being silly, or at least jumping on a bandwagon that was unworthy. I am very grateful for Ryan Maue’s comments (8:39 am and 10:01 am). I think there is great importance in geological hazards studies and these becoming-more-accurate meteorogical studies. The more people wherever they live who can be warned if significant danger is predicted, the better.
    My greatest concern is that people be given the respect and freedom to accept or decline the warning if it means moving out of their “homes”. Given the blood and sweat and years it takes to develop a small plot of your own on this Earth, as long as you retain the choice — it is your decision to stay or leave — then I am supportive of this kind of warning. Let the market be the judge as to the accuracy or failure of a warning, as long as people are aware of the AMOUNT of uncertainty within which these scientists must work. The weather? Ohmygod! In Southern CA it never happens as the forecasters suggest.
    Overall, I applaud these attempts to understand Earth and its weather (and geology). The more people who can benefit and can act to save their lives, families, and livehoods, the better. Pakistan can use this help as least as much as other countries.

  42. Emphasis added:
    Now, a new scientific study that retrospectively examines the raw data from these computer models, has confirmed that, if the information had been processed, forecasters could have predicted extremely accurate rainfall totals 8-10 days beforehand.
    The study also finds that the floods themselves could have been predicted if this data, which originated from the European Centre for Medium-Range Weather Forecasting (ECMWF), had been processed and fed into a hydrological model, which takes terrain into account.

    Am I the only one who thought that amounted to “If only they had had a bigger faster computer…”? You know, like the one the UK Met Office puts to such good use, which it wants to upgrade to a bigger and faster model to do even more excellent work?

  43. This output is can be useful, but should never be confused with real-world data.
    Measurement data, furthermore, are NOT always processed; sometimes they’re merely recorded. (You can call that processing “if you want to be pendantic. [sic]”) The temperature outside the house right now, for instance, needs no processing– unless, of course, you’re Jim Hansen.
    #######
    let me be clearer for you. All data is theory dependent. Sometimes the theory is explicitly applied , other times it is implicit . Do you really think your thermometer “measures” the average kinetic energy of molecules? Thermometers are proxies for temperature. very good proxies, but proxies. It’s theory (models) all the way down.
    Put another way, instruments are embodiments of theory, analog processors if you like. Thankfully the theories they embody are not in serious question so we call their outputs “data” or “observations”

  44. I believe that Piers predicted the opposing hot & dry area to the north in Russia. Some time before the floods began he also tried to warn of the coming floods in Pakistan, but nobody paid any nevermind. He said both conditions were caused by the Jet Stream going into a “locked” mode, forming a closed loop. We have one of those loops sitting over the PNW causing havoc to rain down upon the rest of the US.
    Ask Piers when the loop will break. He says he knows why they form and when they will end.
    Let the GCM’s do likewise, and let’s see who wins.

  45. To those who have commented on our Bangladesh stuff:
    When we first went to Bangladesh to define a strategy for forecasting floods my thoughts were”this can’t be two difficult”. All one has to do is uses (a) all upstream data from India (b) ensemble rainfall forecasts and (c) a good hydrology model. We had (b) and developed (c). But we found out quickly that India does not provide any streamflow data to Bangladesh. In fact, India sates do not share their river data with each other. Its all to do with water rights and impending challenges to treaties. So we had to “synthesize the Ganges and Brahmaputra basin river flow” using the precipitation data. I won’t bore you how we did this (read the BAMS article if you are interested).
    Although the procedure was a little more difficult and unique and not quite as simple as Maue’s “nothing special” or whatever, the trick was to get people at the village level to use the forecasts. This is why we made 17 visits to Bangladesh over the years. As it stands, I think Bangladesh has arguably one of the best probabilistic flood forecast systems in the world.
    For those of you who commented on probability forecasts: There is a simple reason why we do that. It allows the determination of risk. If we define risk by
    risk=probability x cost
    a person quantify a decision being it crossing a road in NY or evacuating a village in Bangladesh or Pakistan. One sets some limit of probability knowing the cost of what would happen if the event occurs. I think it is Figure 11 (can’t remember) in the BNAMS article. The system forecast no false positives although floods arrived a day before or later.
    Going back to Maue’s dismissal, I think the “very special” aspect of what we did was get the people to use them!
    PW

  46. Thanks to Peter Baxter, Mosh & Ryan for comments.
    I think Peter you are maybe too sensitive to Ryans apparently dismissive comments, I don’t think they were meant that way.
    I am usually quite dismissive of GCMs but if they can be employed for relatively short range forecasting in this manner then great, I am all for it.
    As Peter says, this paper is really a sort of feasibility study. I don’t think we should allow our prejudices get in the way of what could be significant work. It’s certainly more valuable than trying to scare the crap out of people over what might happen a hundred years hence.
    DaveE.

  47. Peter,
    Making 17 trips to Bangladesh to help local people better understand and use rainfall forecasts is an enormous commitment. Well done.
    The fact that India won’t share its data within its own states and knowing Pachauri is head of the IPCC, and the lack of data sharing, ignoring the FOI requests, well the irony wasn’t lost on me.
    Congrats to you, a person who steps right in to help people directly as a scientist.

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