Seven said:
A river that is 100 miles long will have a 100 year flood once a year.
Rain is outdoors.....
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Last: 19 days ago by ABATTBQ87
Pojections into major,flood,stage at Rosharon now. Eff this noise.
Right so 1/100 is .01 or 1%. The statement was meant to be read that if that were to happen along the hypothetical river it would be the statistical average. We have had 5 "1/100 events" happen in the last 4 years
Seven said:
Right so 1/100 is .01 or 1%. The statement was meant to be read that if that were to happen along the hypothetical river it would be the statistical average. We have had 5 "1/100 events" happen in the last 4 years
That's not at all how the math works my friend.
Where you seeing that? It is just hot as hell and oppressive. Forecasts wobble between call Noah and 20%. Not a drop of rain to be seen.
The issue is a combination of the wettest 4 years in Texas history, by far, combined with political cronyism damming up Richmond/sugar land. This means that what used to be 100 year flood in the Brazos River basin is not anymore. The question is, what will Mother Nature do going forward. We know politics is corrupt so that won't get much better. The question is what will Mother Nature do.
FWIW the irony is that the global warming alarmists project the Brazos River basin to get hotter and drier outside of more frequent hurricanes. So their model actually helps me.
FWIW the irony is that the global warming alarmists project the Brazos River basin to get hotter and drier outside of more frequent hurricanes. So their model actually helps me.
One, thats based off historic data. Not an unlimited amount of data. Two, theres a 64% probability that there will be AT LEAST one 100-yr event within a 100-yr timeframe. The 100-yr flood just means, on average, one 100-yr event is expected to happen in any given one hundred year time frame. But some time frames will have zero 100-yr events, thus other time frames must have more than 100-yr event in order to average out.
Do you freak out when you roll a die six times and each number doesn't occur exactly once each? That's the expected outcome. And yet, I guarantee you could count on one hand (less actually) the number of times thats occurred in your life. And that only requires six discrete possible outcomes. Not an infinite (continuous) number of possibilities.
And yes, as a result of more recent data, I believe efforts are underway to update what we classify to be certain events. The old NOAA maps were developed decades ago. We have more and better data now.
But that doesn't change the underlying statistical methodology.
I will also state, given the speed of the economy and the potential damage these days, what was once acceptable in terms of economic designs may be outdated. Designing for a 100-yr event made sense at one point (or for certain areas). More economically sensitive areas may justify increasing to a more severe event. However, such evaluations cannot be undertaken lightly; when at the "edges" of the distribution, the "bang for your buck" or "efficient use of resources" diminishes because you gain very little protection for dramatic increases in costs since the size of the events does not scale linearly, and neither do the costs associated with the necessary protections; it's a double whammy.
Do you freak out when you roll a die six times and each number doesn't occur exactly once each? That's the expected outcome. And yet, I guarantee you could count on one hand (less actually) the number of times thats occurred in your life. And that only requires six discrete possible outcomes. Not an infinite (continuous) number of possibilities.
And yes, as a result of more recent data, I believe efforts are underway to update what we classify to be certain events. The old NOAA maps were developed decades ago. We have more and better data now.
But that doesn't change the underlying statistical methodology.
I will also state, given the speed of the economy and the potential damage these days, what was once acceptable in terms of economic designs may be outdated. Designing for a 100-yr event made sense at one point (or for certain areas). More economically sensitive areas may justify increasing to a more severe event. However, such evaluations cannot be undertaken lightly; when at the "edges" of the distribution, the "bang for your buck" or "efficient use of resources" diminishes because you gain very little protection for dramatic increases in costs since the size of the events does not scale linearly, and neither do the costs associated with the necessary protections; it's a double whammy.
Rain chances have gone up. Y'all stay safe.
Nasty in SW Katy right now but it looks really
bad south of us... farmer/cbr, y'all stay safe. Hope it stays in the banks
bad south of us... farmer/cbr, y'all stay safe. Hope it stays in the banks
I'll try to not get too far out into the weeds here. Heck I've probably typed this exact post earlier in this thread...
The "100 Year Flood" is first of all, misnamed. It should be the 1% chance flood. But even that isn't correct. It's the flood that results from a 1% chance rainfall event. These rainfall tables, called hyetographs, are produced by NOAA. They have a bunch of them. They produce a 1% rainfall for the 2 min, 5 min, 10 min, 30 min, 1 hr, 2 hr, 6 hr, 12 hr, 24 hr, 48 hr, and maybe a few other storms. Don't hold me to those exact durations, but if memory serves that's pretty much right. Then you have to put each one of those durations over an aerial extent. Every one of those can produce a 100 year event. There's nothing to say that the "flood" from each of those storm durations will be the same. In fact they won't be the same. FEMA contractors only model the 24 hr event, though if memory serves they do run the models on a saturated watershed. In the end there are a crap ton of variables that are used to ultimately put 1 line on a map and they call that line the 100 Year (1% chance event) flood plane.
The "100 Year Flood" is first of all, misnamed. It should be the 1% chance flood. But even that isn't correct. It's the flood that results from a 1% chance rainfall event. These rainfall tables, called hyetographs, are produced by NOAA. They have a bunch of them. They produce a 1% rainfall for the 2 min, 5 min, 10 min, 30 min, 1 hr, 2 hr, 6 hr, 12 hr, 24 hr, 48 hr, and maybe a few other storms. Don't hold me to those exact durations, but if memory serves that's pretty much right. Then you have to put each one of those durations over an aerial extent. Every one of those can produce a 100 year event. There's nothing to say that the "flood" from each of those storm durations will be the same. In fact they won't be the same. FEMA contractors only model the 24 hr event, though if memory serves they do run the models on a saturated watershed. In the end there are a crap ton of variables that are used to ultimately put 1 line on a map and they call that line the 100 Year (1% chance event) flood plane.
The emergency ticker on the ABC affiliate here in Corpus is scrolling a message that if you are in Freer Texas right now, you are basically ****ed.
STX Ag said:
The emergency ticker on the ABC affiliate here in Corpus is scrolling a message that if you are in Freer Texas right now, you are basically ****ed.
South Texas take cover. Stay safe.
Resistance to tyranny is obedience to God.
North of El Campo near Garwood.
Rocking and rolling right now. Pretty insane weather I don't think I have seen similar since we moved here.
Hail starting to hit now.
Rocking and rolling right now. Pretty insane weather I don't think I have seen similar since we moved here.
Hail starting to hit now.
I've got some drainage work to do... water is 1/4 inch deep just pouring through my garage... House is higher though.
Spring, TX
Spring, TX
Have a ranch just south of Columbus, is it that bad?
Resistance to tyranny is obedience to God.
We have gotten 1.5".
Brief hail, extremely spotty weather.
Intense visuals and lots of cloud to ground lightning.
Nothing terrible though.
Brief hail, extremely spotty weather.
Intense visuals and lots of cloud to ground lightning.
Nothing terrible though.
Western side of Spring Branch in Houston took a beating with golf ball to tennis ball size hail...
Have a roof leak after that now. 5+ inches of rain already tonight
Have a roof leak after that now. 5+ inches of rain already tonight
A 100 year even isnt based on a 100 year time frame. There is a 1:100 chance - or 1% probability - that such an event happens on an annual basis.
I really wish that the terminology would change.
I really wish that the terminology would change.
Grapefruit sized hail reported at Lake Livingston.
Brad06ag said:
Western side of Spring Branch in Houston took a beating with golf ball to tennis ball size hail...
Have a roof leak after that now. 5+ inches of rain already tonight
I haven't seen a roof leak yet in mine. But am in western spring branch north of I10 and got one busted out window on the house from the hail, it even dented the window frame. Siding is all dented, a couple limbs down, and dents in both vehicles so tomorrow will be fun assessing the rest of the damage. Since the road is flooded and if it keeps it up might not be able to make it to work.
The down draft that knocked the power out out there looked like it might have been a little tornadic, was out looking at the storm and hail and spooked me pretty good and I went for the center of my house. sky turned green a little as well but that might have been the transformers blowing or whatnot.
Victoria is a slight sound show with some light rain and lightning. For now.
I lived in Kansas back around '91 for about a year and a half. If the tornados didn't get you the hail did for sure. Biggest I saw was .50cent piece size and the damage was amazing. I cannot even fathom what Livingston has gone through if that is true.
I lived in Kansas back around '91 for about a year and a half. If the tornados didn't get you the hail did for sure. Biggest I saw was .50cent piece size and the damage was amazing. I cannot even fathom what Livingston has gone through if that is true.
Schmellba, thats where the 100-yr term comes from. It is the 100-yr recurrence interval, such that on average, over an infinite period of time, there will be one 100-yr event per the number of 100 year periods included in that time. That does not mean only one event per any 100 yr period.
Its the same as rolling a dice or flipping a coin. The return period (or recurrence interval) for tossing a fair coin and getting heads is two flips. It does not mean that in any two flip interval, you are guaranteed only one heads. On the contrary, it simply means, that on average, if you flip a coin 50 times, you would expect to see 25 heads. The distribution of those heads within the 50 flips will be all over the place.
Same thing with dice. The return period (or recurrence interval) for rolling a 3 is 6 rolls of the dice if you roll a fair die 600 times, on average, you would expect 100 each of 1, 2, 3, 4, 5, & 6. Thus, the recurrence interval is 6 rolls.
With continuous events measured with time as the interval, the correct nomenclature is in fact years (or minutes, or days). Thus, a storm that has 1% chance of happening in any one year, has a recurrence interval of 100-years. This is simply the language of statistics.
But, you should no more expect to have only one 100-yr event within a 100 year period anymore than you would expect that if you rolled a dice 6 times, that you would get each number exactly once. There will be periods with multiple 5s hitting one right after another. Just like there will be periods of ten, twelve or fifteen rolls in which no 5s come up. But on average, you will roll 100 5s in 600 rolls of a fair dice.
Its the same as rolling a dice or flipping a coin. The return period (or recurrence interval) for tossing a fair coin and getting heads is two flips. It does not mean that in any two flip interval, you are guaranteed only one heads. On the contrary, it simply means, that on average, if you flip a coin 50 times, you would expect to see 25 heads. The distribution of those heads within the 50 flips will be all over the place.
Same thing with dice. The return period (or recurrence interval) for rolling a 3 is 6 rolls of the dice if you roll a fair die 600 times, on average, you would expect 100 each of 1, 2, 3, 4, 5, & 6. Thus, the recurrence interval is 6 rolls.
With continuous events measured with time as the interval, the correct nomenclature is in fact years (or minutes, or days). Thus, a storm that has 1% chance of happening in any one year, has a recurrence interval of 100-years. This is simply the language of statistics.
But, you should no more expect to have only one 100-yr event within a 100 year period anymore than you would expect that if you rolled a dice 6 times, that you would get each number exactly once. There will be periods with multiple 5s hitting one right after another. Just like there will be periods of ten, twelve or fifteen rolls in which no 5s come up. But on average, you will roll 100 5s in 600 rolls of a fair dice.
Cromagnum said:
Grapefruit sized hail reported at Lake Livingston.
Where have you seen that? Also north end of Livingston like riverside or where abouts?
Except that isnt the definition of a 100 year event.
It is crappy nomenclature that causes a lot of confusion, but your definition is not correct. The probabilities might come out to be the same and if you extrapolate it over a 100 year period then your definition works, but it has absolutely nothing to do with a 100 year unit of time in any capacity. It is all about the probability of happening at a given location in any given year.
A 100 year storm has a 1% probability of happening in any given year. A 500 year strom has a .002% probability of happening in any gven year. A 50 year storm has a 2% probability of happening in any given year.
Quote:
A100-year storm is the amount of rainfall measured at a certain location, during a specified length of time, that has a 1% chance in any given year of being equaled or exceeded.
It is crappy nomenclature that causes a lot of confusion, but your definition is not correct. The probabilities might come out to be the same and if you extrapolate it over a 100 year period then your definition works, but it has absolutely nothing to do with a 100 year unit of time in any capacity. It is all about the probability of happening at a given location in any given year.
A 100 year storm has a 1% probability of happening in any given year. A 500 year strom has a .002% probability of happening in any gven year. A 50 year storm has a 2% probability of happening in any given year.
Everything correct, except a .002% is a 50,000 year event.
schmellba99 said:
Except that isnt the definition of a 100 year event.Quote:
A100-year storm is the amount of rainfall measured at a certain location, during a specified length of time, that has a 1% chance in any given year of being equaled or exceeded.
It is crappy nomenclature that causes a lot of confusion, but your definition is not correct. The probabilities might come out to be the same and if you extrapolate it over a 100 year period then your definition works, but it has absolutely nothing to do with a 100 year unit of time in any capacity. It is all about the probability of happening at a given location in any given year.
A 100 year storm has a 1% probability of happening in any given year. A 500 year strom has a .002% probability of happening in any gven year. A 50 year storm has a 2% probability of happening in any given year.
He clearly said one storm every hundred years - otherwise known as 1% in any given year. What are you arguing?
Only one way to settle this whole argument
A duel
And you can only use pistols from the 1700's
A duel
And you can only use pistols from the 1700's
yes it is bad to get this much rain, not as bad as Alvin in 1979,45 inches in 24 hours
might still be north American record
might still be north American record
OE_Ag11 said:Cromagnum said:
Grapefruit sized hail reported at Lake Livingston.
Where have you seen that? Also north end of Livingston like riverside or where abouts?
https://www.spc.noaa.gov/climo/reports/today.html
http://www.stormersite.com/hail_reports/west_livingston_texas/2019
The Alvin record was 43 inches, and it was broken by Harvey over near Port Arthur I believe.petebrown74 said:
yes it is bad to get this much rain, not as bad as Alvin in 1979,45 inches in 24 hours
might still be north American record
didn't know that, thanks for the updated info.have a great day
Harvey didn't break the Alvin record I don't believe (not over a 24 hour period anyway). Alvin's 24 hour record was broken by an event in Hawaii within the last year or two.txags92 said:The Alvin record was 43 inches, and it was broken by Harvey over near Port Arthur I believe.petebrown74 said:
yes it is bad to get this much rain, not as bad as Alvin in 1979,45 inches in 24 hours
might still be north American record
in my feeble little brain Hawaii is not part of north America, so the record stays in texas
I was referencing the US record.petebrown74 said:
in my feeble little brain Hawaii is not part of north America, so the record stays in texas
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