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[quote user="dehusman"]Before everybody gets too excited about the flood gauge data, a significant detail is that the flood data is not updated on a real time basis, it is generally updated about hourly with a little lag. [/quote] The USGS gage data is updated every hour with the current discharge and levels. The delay is about 5 to 10 minutes. Example: Most recent instantaneous value: 1410 07-11-2018   08:15 CDT displayed at 8:21 CDT As the update is at the same time hour for hour your delay is max. 15 minutes if you know when to look. [quote user="dehusman"]Since it takes several data points to determine a trend, it could take several hours to even detect that something was shifting in the water levels. If it was a short term event, like a sudden rise and drop, over a short period, lets say 3-4 hours, it could be over by the time the event was detected.[/quote] When I read you post I get the impression that this is rocket science. This is observation and simplest mathematics. Upriver: On June 21, 2018 0:00 am there had been a rise of about 3 ft within the last 10 yours upstream. At about 10 am there was another 5 ft rise. After a few hours pause there was a rise of additionally 3 ft crossing the Major Flood Mark. Down river: On June 21, 0:00 am there had a rise of 2 ft within 10 hours. In contrast to upriver the level rose constantly without pause by 8 ft within the following 24 hours. So there was early warning, more than the 3-4 hours you talked about. Everything else is constantly watching. [quote user="dehusman"]The downstream gauge is a lagging indicator, it tells you what happened, not what is going to happen, plus it lags the upstream gauge by probably an hour or more, being several miles away. By the time you could confirm that there was a difference in the trend and see a change in the downstream gauge, it would be somewhere over 3-4 hours. [/quote] the gage is about 4.5 miles downstream but it showed the same tendency at the same time! So there was no delay. For me that indicates that a lot of water came into Rock River after the upriver gage. Edit: The upriver gage still rose at the time of the accident, so no need to think the situation at Doon was much different than Rock Valley. dehusman: There are also several tributaries from multiple directions feeding into the main river, in any case you would expect the downstream flow to be larger than then upstream flow, since there aren't gauges on all the tributaries it is pure speculation to assign the majority of it to one tributary. There are a number of tributaries. Looking at their watershed areas makes my assumption that majority of the balance of the discharge an adjucated guess.  dehusman: This is all really cool for monitoring an event over a period of days or weeks (done that), but its not real handy for predicting something short term on a real time basis.  After you get 6-12 hours of trend, you can make some pretty good guestimates of where it might go.  They do provide forecasts, but like all weather forecasts they are estimates and they can be off by time and elevation (seen that too). About 3.5 hours before the accident the Rock Valley gage 4.5 miles south of Doon showed a near record level with a discharge only exceeded twice in 70 years. Do you need more indication that this is not the typical yearly spring flood? There was ample warning, there was enough time to observe and even a last warning shot 3.5 hours before the accident. dehusman: Its pretty easy to figure out what caused car crash after the event, but what the railroad's situation is trying to figure out if there will even be a crash, when and where it will happen, before it happens, all while riding in the car.  Higher degree of difficulty. I have tried to show what information about the flood should have been known at BNSF as basis for their decision how to operate the oil train. I did it afterwards but what I found is available online almost simultanously with event. I don't try to find the reason for the accident. I think the appropriate care and more Rule 1.1.1 especially with an oil train would have reduced the aftermath. It is an opinion and I might be wrong. I went into this detail as some posters here tried to play down the high water despite the facts. One can value facts differently, an the BNSF apperently did. The railroad might have had all the information and come to the conclusion there was no reason to reduce the speed. Hopefully the results of the internal investigation will show up. Regards, Volker
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