[HN Gopher] New Orleans levees passed their first major test ___________________________________________________________________ New Orleans levees passed their first major test Author : yread Score : 68 points Date : 2021-09-05 14:20 UTC (8 hours ago) (HTM) web link (www.nationalgeographic.com) (TXT) w3m dump (www.nationalgeographic.com) | selimthegrim wrote: | I'm not sure they were really tested what with the track to the | west. | ahnick wrote: | As the article rightly points out, levees will do nothing for a | slow moving hurricane like Harvey that dumps tons of rain or for | a large cat5 hurricane with storm level surges that are much | higher than Ida. The place is sinking while sea level rise is | already locked in with current levels of CO2 in the atmosphere. | The only solution is relocation, but nobody wants to hear that. | It is an inevitability that New Orleans will be uninhabitable. | The only question is when. | malkuth23 wrote: | That might be the only solution you can think of, but that does | not make it the only possibility. What you are really saying is | you don't think New Orleans is worth saving. New Orleans | infrastructure consists of far more than just levees. Our | pumping system is currently rated to remove 1 inch of rain the | first hour and 1/2 inch each additional hour. We can remove | this much rain with wooden screw pumps that still run on 25 | cycle power. Upgrading or adding to the pumps in New Orleans to | handle more water makes far more sense than giving up on what I | believe is the most special city in America. | | https://www.atlasobscura.com/articles/new-orleans-wood-screw... | | You say that nobody want to hear your hot take on abandoning | New Orleans, a city with one of the most important ports in the | country, yet I hear this proposed constantly (and upvoted) by | people that have almost no specialized knowledge of | infrastructure. It is armchair nihilism and imo not helpful at | all. The army corps of engineers thinks differently. Agencies | like the CPRA are working to restore land on the coast. There | are ways to mitigate the damage, to reduce the risk and protect | the city. Yes it is expensive. No it is not cheaper than losing | our ports, our people, our culture. | | https://gnoinc.org/news/ports-of-south-louisiana-new-orleans... | | Soon enough, if we don't invest in NOLA, you will likely be | right, but I doubt it will be because there was no other | option. It will be because we as a country made a huge mistake | and failed to act. | | The truth is, a lot of America does not care about people or | cities in the south. New Orleans gets a bit more attention | because tourists had a good time on Bourbon once, but overall | it is treated as an oddity and not an essential piece of the | both the economic and cultural fabric of America. There are | people down here that feel the same way about California with | its earthquakes and wild fires and I make similar arguments | when arguing with them. Speaking of which, NYC fared far worse | against the remnants of a storm we took head on. Should we | abandon it or improve it? Hell no we should not give up on NYC, | nor SF with it's earthquakes, or LA with it's water shortages, | or Baltimore with its crime, or Detroit with its collapse of | industry and definitely not New Orleans. | ahnick wrote: | It's not the only solution I can think of, but it's the only | practical one. Sure you could build giant sea walls around | the area or bring in land and start literally raising all the | buildings above sea level (similar to what Chicago did in the | mid 1800s), but you are talking billions of dollars, maybe | hundreds of billions. Once you get into that situation it | just makes sense to move everything upstream and perhaps only | fortify key infrastructure like ports until even those pieces | have to be relocated. | | The army corps of engineers is not given the option of not | trying to save New Orleans. People in government tell them to | go build levees and protect the city from flooding and they | do the best job that they can, but they are fighting a losing | war. The time to introduce relocation assistance programs is | now, so you spread the cost and process out over many years; | otherwise, you are going to just end up doing the same thing | later, but it will cost more money and more lives will have | been lost. | SmellTheGlove wrote: | How does New Orleans compare to the Netherlands in terms of | long term flood risk? | candiddevmike wrote: | This is my fear as well. All of these coastal cities are at | risk for relocation, who's footing the bill for the government | to buy the houses, relocate the people, provide them new | houses, jobs, etc? There is a ton of self interest in keeping | people in places like New Orleans (and even growing the | population), but we need to accept the reality that these | places will be uninhabitable in the near future. | | I already foresee a bunch of folks getting tons of money for | Hurricane Ida claims only to rebuild houses in the same exact | spot. We should encourage them to take the money and move away, | not stick around. | treeman79 wrote: | Government doesn't need to do a thing. | | Assuming flood insurance prices are realistic (not propped up | by government), eventually no new construction will happen | because no one will approve/afford insurance. | | Existing places will get cheaper / hell hole as rates keep | going up. | | Federal flood insurance has distorted market prices | drastically in many places | MisterBastahrd wrote: | New Orleans and Port Fourchon are pretty vital to US economic | interests because of their ports. | Animats wrote: | It's mostly river deltas that have this problem. A small sea | level rise reduces flow at the river outlet, causing flooding | out of proportion to the sea level rise. | | The only big river delta in the US is the Mississippi. East | Asia has far worse problems. Most of China's port cities are | on river deltas. Tapei is on a river delta. Ho Chi Min City | is on a river delta. Singapore is on a river delta. These are | all areas where the land to water slope is very low. | | The western US is mountainous enough that there's more than | enough land rise to prevent flooding more than a short | distance inland. Even in places that look flat, like LA near | Venice, go three blocks inland and you're tens of feet | higher. Places that built on fill, such as San Francisco and | Foster City, do exist, but are small enough for barriers and | not fed by upstream rivers. | bostonsre wrote: | I can't imagine flood insurance is very cheap in these | locations and I don't think this is an imminent domain type | situation where the government would buy houses. At some | point, people will be ruined financially and won't be able to | rebuild. | | Other wealthier places may be able to use municipal bonds to | fight sea level rise. In the valley in Foster City, the | choice was between pricey flood insurance and a cheaper | municipal bond to construct a robust levee and the latter was | chosen. The city is small enough and the residents were | wealthy enough to do it. | | I'm kind of curious if anyone will attempt to damn up or | construct locks under the golden gate bridge. I think the | valley could be wealthy enough to do it. | mcast wrote: | People said the same cynical comments about not being able to | build skyscrapers alongside the coast of New York City, which | would be impossible to excavate deep underground without | flooding the city. We should look into improving the | infrastructure and innovating our urban planning layouts to | better handle these natural disasters rather than just | abandoning them. Yes, hurricanes will continue to strengthen, | but improving building codes and adding more canals and | waterways for flood control can mitigate many of the deadly | problems. For what it's worth, New Orleans is a historic city | with a rich culture. | kibwen wrote: | _> For what it 's worth, New Orleans is a historic city with | a rich culture._ | | Nobody wants to lose New Orleans. It's a great city. But the | problem is accurately summed up by the OP: "How much can | places where millions of people live be fortified? At what | cost? And who pays for it?" | | The only good news is that the Port of South Louisiana is the | biggest and arguably most important port in the Western | Hemisphere (and that's without even taking into account the | Port of New Orleans or the Port of Baton Rouge, both in the | top 10). There is enormous nationwide economic and | geopolitical incentive to protect the city. The bad news is | that New Orleans would be sinking even without rising sea | levels. | selimthegrim wrote: | The article fails to point out that New Orleans' drainage | system is actually better than Houston's. | MR4D wrote: | I live in Houston and can attest to that being ridiculously | true. This is completely due to government incompetence | (mostly local, not state or federal). The lack of remediation | after Harvey is just sad. So many missed opportunities. Bill | White was the last major who did anything about it, and he | took a long term view that his successors have basically | ignored. | dangerbird2 wrote: | Moving ungodly volumes of rainwater away from homes and out | of the streets is one of the few things New Orleans' | infrastructure does _really_ well. I remember times when I 'd | be walking down the sidewalk through knee-deep water to get | to class, and on my way back 45 minutes later it's basically | all gone. A Harvey-level rainstorm would certainly cause | damage, but NOLA would probably handle it better than any | major city in the country. | malkuth23 wrote: | Our pumps are so old many are still using wooden screws and | run on 25 cycle power. Think how much water we could pull | out if the system was upgraded? New Orleans is more | prepared to survive than any other city with a few hundred | miles of it, including mega cities like Houston. | MisterBastahrd wrote: | Vastly better than Houston's. Not even remotely comparable. | The same rainfall amount that would put Houston under water | would have a few streets and underpasses rendered impassible | for a few hours in New Orleans and the surrounding areas. My | hometown was on the east side near the eyewall when the storm | stalled over them for a few hours. Tons of wind damage, | virtually zero flooding aside from parking lots and one levee | that was damaged from the storm surge. | selimthegrim wrote: | Do you think the surge in your hometown was high enough the | old levees wouldn't have handled it? | MisterBastahrd wrote: | Those are the old levees. They didn't even approve the | new levee system for that area until this year. | Spooky23 wrote: | In some ways, levees make it worse by damaging the delta, which | ultimately protects the city. | MisterBastahrd wrote: | Nope. Different levee system. The system that harms the delta | is the one that keeps the Mississippi from cutting a path | wherever it wants. This other one is a system that simply | protects populations from storm surge. | reddog wrote: | >New Orleans will be uninhabitable. The only question is when. | | A very, very long time from now. According to the IPCC Sixth | Assessment Report sea levels are projected to rise between .57 | and 1.25 meters by 2120. So unless you have waves currently | lapping against your back porch you, your kids, your grandkids | and your great-grandkids will be OK in NO. | | For context, sea levels have risen about .3 meters over the | last hundred years and we have adapted without city evacuation | and relocation. | | https://sealevel.nasa.gov/ipcc-ar6-sea-level-projection-tool | ahnick wrote: | The midway point in the sea level tool you linked is actually | 1.41m by 2100. That's 4.6 feet of sea level rise by the end | of the century and this is based on our current models where | we are continuously discovering more and more positive | feedback mechanisms that is accelerating sea level rise. | (https://www.science.org/news/2020/11/seas-are-rising- | faster-...) Now those levee walls that were originally 13 | feet high are now less than 9 feet from the water and no | longer really capable of doing the job they were designed | for. So we better build bigger walls to keep all the water | out, so let's go back and spend billions and billions more to | have bigger walls, which by the way encourages more and more | people to move into flood prone areas. Then you really set | things up for a black swan event where something unexpected | causes a levee failure (b/c that's never happened before) and | then a bunch of people die. | | So maybe you and your kids MIGHT be okay, but your grandkids | and your great-grandkids? probably not. | reddog wrote: | >The midway point in the sea level tool you linked is | actually 1.41m by 2100. | | No. Not sure where 1.41m is coming from. Take a closer look | at the linked NASA site. You will need to click on the link | labled "View global projection" (sorry, there isn't a | direct link). You will see a graph labeled "Projected Sea- | Level Rise Under Different SSP Scenarios". The midpoint | highest rise of all seven of the scenarios for 2100 is just | .88 meters and that's for the most pessimistic SSP5-8.5 | _Low_ _Confidence_ scenario. The more likely scenarios are | about 1-2 feet. | | Your great-grandkids will be fine. | nknezek wrote: | 1.41m by 2100 is the projection for "Grand Isle", the | closest location in the model to New Orleans. Sea level | and sea level rise is not uniform worldwide, so local | predictions are very important. This is also true for | temperature and other climate change impacts, and is one | of the biggest improvements in the latest IPCC report. | | It looks like all model scenarios agree fairly well out | to 2100 both in the global projections and in projections | for Grand Isle. Thus, I'd wager good money that New | Orleans will see 1-2m sea level rise by 2100 regardless | of any climate mitigations we perform. | selimthegrim wrote: | Grand Isle (which Ida did a number on) is well south of | NOLA in Jefferson Parish, and not part of the metro area. | It exists for fishing and tourism. | Muromec wrote: | >The place is sinking while sea level rise is already locked in | with current levels of CO2 in the atmosphere. | | Biggest airport in The Netherlands is 3 meters below the sea | level, but at least we don't have hurricanes here, just North | Sea | | https://en.wikipedia.org/wiki/Amsterdam_Airport_Schiphol | kibwen wrote: | Europe is generally protected from hurricanes due to how far | north everything is, but as the north Atlantic warms tropical | storms will become more frequent, potentially graduating into | legitimate hurricanes every once in a while. | beerandt wrote: | This is alarmist BS. | | I worked on the surveys and cors equipment that directly | measures subsidence in Louisiana, and have worked on many of | the levees and other coastal civil works. | | Relocation? For a problem that hasn't happened yet and isn't | likely to happen in the foreseeable future is absurd. | | New York City is at a much greater risk and will be inundated | long before New Orleans. | | The fastest rate of subsidence in New Orleans is/was due to | organics in the soil decomposing once the groundwater table was | lowered (drainage projects going back 300 yrs), allowing oxygen | to infiltrate. This decomposition is mostly complete in most | areas of the city. | | Piles under everything from skyscrapers to personal homes | penetrates the organic layers, so buildings don't subside even | if the ground does. | | The biggest risk to the city and state is environmental | activists, the EPA & the Army Corps of Engineers, and the | largely untouchable Mississippi River levee system, preventing | the delta land building process that counteracts subsidence by | depositing new sediment in yearly floods. | | Additionally, erosion/ runoff prevention and dams through out | the Mississippi, Missouri, and Ohio river watersheds have | decreased the amount of sediment flowing down river, and | results in less sediment available for natural land building. | | The coastal barrier marshes and islands are dying because we've | stopped the natural processes that sustain them. Each mile of | marsh results in the natural lowering of storm surge by 1/2' to | 2'. | | The federal government, environmental groups and others fight | the restoration of these natural processes. For example, they | argue fresh water introduction will hurt dolphin populations in | coastal bays, but they are only capable of being there in the | first place because of man made interference: the bays were | freshwater until the levees cut off their natural supply of | freshwater. | | As for global warming? Infrastructure, business and homes are | amortized at 30yrs or less. Maybe up to 50yrs for very large | civil projects. | | Worst case sea level rise estimates easily gives New Orleans | 300+ more yrs, likely much longer, a time frame longer than the | current age of the city. | pfisch wrote: | It is and it isn't. His scenario won't happen but what will | happen is fairly similar. | | No one is going to make large capital investments in a city | that gets blown away all the time. Every time New Orleans | takes a big hit like this people leave, and less money is put | back into the city. | | The population of New Orleans was higher in 1980 than it is | now. I am from New Orleans, and since Katrina the | infrastructure has been getting worse, not better. | | There probably isn't going to be some big dramatic event that | kills New Orleans. It will just keep shrinking and pulling in | towards the French Quarter as it gets hit repeatedly by | extreme weather events. It will just become smaller and more | impoverished over time until it is maybe abandoned at some | distant point in the future. | | It will be a death by inches. | beerandt wrote: | Cities across the country will die much sooner from | economic and political reasons than New Orleans will die | from subsidence. (Although New Orleans is likely included | in that first set as well, based on current leadership.) | | But we don't discourage economic development in those | places. My amortization comment was perhaps not explicit | enough, but as long as people think the city will last | beyond amortization periods, future | abandonment/inundation/end-of-days predictions are not a | rational reason to preclude investment. | | Most businesses shoot for a payback period of 10 years or | less. | | I expect you're right about slow death, but it won't be for | climatic or geologic or hydraulic reasons. | | _Fear_ of those reasons might contribute, but then we 've | gone full circle back to "alarmist BS". | pfisch wrote: | You're being unrealistic about the reality of living in | New Orleans and the level of capital investment in New | Orleans vs Baton Rouge or other cities that aren't under | constant threat of destruction. | | People just aren't going to come in and build nice | shopping centers in New Orleans. It isn't happening and | hasn't happened. Why would it when they could build in | another city where it won't get destroyed and it will be | more profitable? | | It is extremely stressful every year watching hurricanes | and wondering if your house is going to be destroyed. | Then when your house is destroyed it is no fun at all to | be involved in gutting it and rebuilding it. On top of | that no one is making investments in the city so it | hardly has any good jobs. | | It isn't alarmist to recognize what is already happening. | The climate is creating more extreme weather events that | are undermining New Orleans. It doesn't need to be some | fake "The Day After Tomorrow" style disaster that people | can easily recognize. It is an insidious, slow, hollowing | out of the city. | | How many water boil warnings have their been since | Katrina? How often has electricity been inconsistent in | the city? I can tell you it happens a lot more now than | it did before Katrina, and it is going to be even worse | after Ida. | beerandt wrote: | Climate isn't the problem with any of those issues, | politics is. | | It's not fear of flooding that prevents anyone from | investing in, eg New Orleans East. It's two decades of | zero policing. | | And there's a reason Entergy continues to operate as a | completely separate corporate entity in the city, and | it's not because "used to be nopsi". | | The water guys can't even operate a billing system, let | alone engineer the distribution network. They ran through | probably a dozen companies post- Katrina just to do an | assessment and map and maintenance plans, and they all | quit for having to deal with the city. | | That's why they can't keep the water on. But an | unnecessary new airport? They had no problem throwing a | billion dollars at contractors for that. | | If people were afraid of sea level rising, they wouldn't | just be moving into another swamp/marsh outside of city | limits or across the lake. People don't want to live at | sea level without a levee on the North Shore, they just | don't want to live in New Orleans, despite the +20ft msl | and up levees. | jsight wrote: | How many homes were destroyed and will need to be rebuilt | due to ida? | selimthegrim wrote: | People are perfectly happy to come and drop hundreds of | millions on developing apartment complexes in the CBD for | some reason, so why not shopping centers? The good jobs | bit I agree with, I am about to leave Tulane with a PhD | and barring some remote offers from Houston I can't find | a means, motive or opportunity to stay here as much as I | enjoy it. | beerandt wrote: | Still gonna argue that's more politics than fear of | flooding. | lostandbored wrote: | Honestly, that is a great a reply. | | I especially agree that some dams on the Mississippi need to | destroyed and have agriculture be moved away from the river, | as the dead zone in Gulf of Mexico is caused by upstream | agriculture states. | ahnick wrote: | 300+ years? And the biggest risk to the city is environmental | activists and the EPA? You must be joking. | | The biggest risk is the fact that according to our best | estimates by 2050 sea level rise will be another 1.5 feet in | that area. (https://sealevel.nasa.gov/ipcc-ar6-sea-level- | projection-tool) For an area that is already on average 7 | feet below sea level. New Orleans topography is basically a | bowl between Lake Pontchartrain and the Gulf of Mexico. | Couple that with stronger and more frequent hurricanes and | there will be few places left to live in New Orleans and the | surrounding area. | | People who give other people a false sense of hope is what | endangers lives and sets up future generations for | devastation. If you really want to help people you need to | break the cycle and subsidize relocation costs for those who | currently live there that can't afford to move. All these | mitigation efforts like restoring the natural coastal | barriers may delay some flooding (so sure do it), but it will | not prevent the inevitable and it is coming much sooner than | 300+ years. | beerandt wrote: | >For an area that is already on average 7 feet below sea | level. | | There are areas as low as -22' msl. Maybe -25'. | | But that's irrelevant, because the edge of the bowl and | protection is at a minimum elevation ~+20' msl and up, | depending on adjustments for things like modeled wave | height. | | Whereas New York's _highest_ protection is currently | something like +8 ', and isn't a closed loop. | | And what's the elevation of the deepest basement/ subway/ | tunnel in NYC? Because I bet it's a lot lower than -22' or | -25' msl. | goatsi wrote: | How is sediment deposition supposed to counteract the | subsidence of land that has anything built on it? | beerandt wrote: | Outside of levee protections, structures are all on piles | above the flood elevation, so floods literally go under the | house. | | Inside levee protections, as the system currently exists, | it doesn't, so houses have to have sand pumped under them | occasionally to fill gaps left by subsidence. | | The house is on piles, so it remains in place. | eloff wrote: | > Worst case sea level rise estimates easily gives New | Orleans 300+ more yrs, likely much longer, a time frame | longer than the current age of the city. | | Your argument depends on this but you give neither numbers | nor citations, so it's unsubstantiated and we have no idea | how true it is. Numbers I've seen, that are bad, but not | worst case are 6' by the end of the century and 20'-60' over | longer timescales. I seriously doubt New Orleans will be just | fine through that. Many coastal cities will have to move. | It's not practical to wall in all of the coast to that | extent. Many cities would end up being islands. | pessimizer wrote: | > Your argument depends on this but you give neither | numbers nor citations, so it's unsubstantiated and we have | no idea how true it is. | | Unsubstantiated _on this thread._ I mean, you can look it | up and find out if it 's true yourself. It's also weird | that you follow it up with numbers of your own, but also no | references, so you must think that's alright to do. | eloff wrote: | You also don't know how substantiated my claims are, but | at least with numbers you could look it up. Parent | provided only an argument from authority. There is no | easy way to falsify it. You'd have to do all the research | from scratch. | dylan604 wrote: | >Piles under everything from skyscrapers to personal homes | penetrates the organic layers, so buildings don't subside | even if the ground does. | | The sinking building in SF would like to differ with this. If | a building is not built correctly, all bets are off. | beerandt wrote: | The problem in San Francisco is entirely different. It's on | poorly designed building. Even if every building in San | Francisco had that problem, it still wouldn't be relevant. | | The problem strata in New Orleans is the top 10-20' of | soil. Mostly whatever's above the pumped-down, controlled, | water table. | | Piles only need to go that deep to suffice, or more | typically until they hit the first layer of sand, which is | stable. Literally every slab house built in New Orleans is | built in these, because before this, everything was on | blocks so it could constantly be raised and leveled. | dylan604 wrote: | >or more typically until they hit the first layer of | sand, which is stable. | | I think this is the first time I have ever seen someone | claim that a layer of sand is stable. But hey, NOLA is | one of the craziest places, so sure, sand is stable | there. | cronix wrote: | Yes, AFAIK the piles didn't go all the way down to solid | bedrock and San Francisco is basically built on a garbage | dump covered over from previous devastating earth quakes, | basically. They were improperly installed and if they had | been the building would likely be fine. So, you're both | right. | bitbckt wrote: | That area of the city is built on infill, but that is by | no means true of most of the city's area. | nickthemagicman wrote: | Nola has the most shipping tonnage of any port in the | hemisphere. | | There's many billions of dollars of port and plant | infrastructure there. | | Its way cheaper and easier just to rebuild the city every few | years and pay to buffer it against disaster than to relocate | all of that. | | Just like it's easier to keep a legacy code base that's working | and making money than fully rebuild it. | | Nola's not going anywhere anytime soon. | selimthegrim wrote: | I mean, the food isn't _that_ much worse in Morgan City long | term. | nickthemagicman wrote: | I bet there's amazing food there. | | They just don't have the Alcoholism. | | Also, if the Old River control system ever fails Morgan | City will be the next New Orleans. | | https://en.m.wikipedia.org/wiki/Old_River_Control_Structure | justinator wrote: | You're right! There's too much money invested - and to be | made! People will just have to suffer. Let's keep our focus | on what's important. | nickthemagicman wrote: | I think most people there would rather the rich chaos of | New Orleans than the cultural blandness of the rest of the | country. | | "America has only three cities: New York, San Francisco, | and New Orleans. Everywhere else is Cleveland" - Tennessee | Williams | | Am currently evacuated from Ida, and drove all the way to | Kentucky from Nola and from what I'm seeing so far, can | confirm that quote is depressingly accurate. | | Why does the rest of the country look like one giant strip | mall from coast to coast? What happened to America? | selimthegrim wrote: | Am in DC, but I toast you with an imaginary glass of | Early Times. | justinator wrote: | Yeah, that was sarcasm. Also eat orphans. | nickthemagicman wrote: | In New Orleans they would throw anything in a frier. | | Have a fried Orphan and catfish basket. | jazzyjackson wrote: | Well going by Hurricane Ida, New Jersey will have to relocate | themselves before New Orleans, but not before they build a | seawall under the Verrazzano bridge. To describe the | destruction of a city as "inevitable" is just admitting you | don't want to spend the billions of dollars necessary to | protect it. | Exmoor wrote: | Somewhat incredibly, Ida killed _far more_ people as a weakened | tropical storm in the northeast after crossing the entire US than | it did as a Cat4 /5 hurricane on the gulf coast. | | From Wikipedia: | | > As of September 4, a total of 70 deaths have been confirmed in | relation to Ida: 27 in New Jersey, 18 in New York, 13 in | Louisiana, 5 in Pennsylvania, 2 in Mississippi, 2 in Alabama, 1 | in Maryland, 1 in Virginia, and 1 in Connecticut. | beerandt wrote: | News coverage is really dropping the ball on this one. It might | not have the optics of Katrina, but it was a far more powerful, | even if smaller, storm. | | Eg: New Orleans, Baton Rouge, and SE LA power outage maps | [0][1][2] | | Based on the damage in south Louisiana, it's a miracle there | weren't far far more deaths. | | The damage to Port Fourchon alone should be national news. | Anywhere from 10~30% of the countries oil flows through there, | depending on how you measured it. And it got a direct hit. | | The gas pipeline fiasco from a few months back? All the | refineries feeding it were shut down for over a week. Wait till | that lag period catches up. | | But for reasons that be, MSM decided this was a non-event until | it got to NYC, and even then a relatively minor one. Hard to | believe they're not downplaying this on purpose. | | [0]https://i.imgur.com/MT1z0n5.jpg | | [1]https://i.imgur.com/HpKJlS4.jpg | | [2]https://i.imgur.com/618PI36.jpg | datameta wrote: | I'm in NYC. Besides walking my dog briefly in the heavy rain | twice I wasn't even aware of Ida until the clear morning after | someone showed me flooded subway photos looking like from the | end of MGS2. I'm not sure it was communicated properly save for | the flash flooding broadcast that could have also come from | just a lesser heavy thunderstorm. | dylan604 wrote: | From what I read, that was the very first time the NWS had | every issued a Flash Flood warning for NYC. Seems like that | might have earned it a little more attention. | | This reminds me of the people complaining about how | destructive the floods in Houston were after Harvey. | Nevermind that the forecasts for days leading up to it were | 40" of rain. What part of 40" of rain sounds like no big | deal? | beerandt wrote: | If you've never had to deal with it, you don't comprehend | the danger. | | I know workers that moved to New Orleans after Katrina to | do the actual post storm cleanup, first hand, and didn't | evacuate for Ida, knowing it was a more powerful storm. | | Some of them had their entire roof(s) blown off and had | 100' pine trees fall through their house while they were | home, riding it out. | | Even seeing the post storm damage doesn't convey the actual | danger _during_ these weather events. | bogomipz wrote: | >"If you've never had to deal with it, you don't | comprehend the danger." | | I don't believe you need to experience something first | hand in order to comprehend the danger. I've never | visited an active conflict zone but I fully comprehend | the danger of traveling to one for a holiday. Conversely | I have friends in New Orleans who didn't evacuate for | Katrina who also didn't evacuate for Ida. They obviously | comprehended the danger very well. There will always be | people who are stubborn, careless or possibly just have a | much higher risk profile regardless of their personal | history. | | It's also odd to think that people wouldn't understand | the danger of flash floods given that in the last 5 weeks | alone we have seen the flash floods in Henan Province | China as well as the flash flooding in Eastern Germany. | These two flash flood events were major international | news stories and you would be hard pressed to not have | seen those images. | pessimizer wrote: | > I've never visited an active conflict zone but I fully | comprehend the danger of traveling to one for a holiday. | | Do you, really? Without even knowing which conflict zone, | or doing any research? All areas of violence have had and | will have a similar danger level? | bogomipz wrote: | >"Do you, really? Without even knowing which conflict | zone, or doing any research?" | | Where did that even come from? I neither stated or even | implied any of that. I haven't visited an active conflict | zone precisely because I did research. It's somewhat | bizarre you would make those assumptions when you know | nothing about me. | bogomipz wrote: | >"I'm not sure it was communicated properly save for the | flash flooding broadcast that could have also come from just | a lesser heavy thunderstorm." | | The National Weather Service Service issued it's first ever | "flash flood emergency" for NYC on Wednesday.[1] It's not | like these are common for the region. | | Alerts went out to cell phones in NJ and NY at 8:41PM EDT | with 3 more alerts following. Why would it matter whether a | flash flood emergency accompanies a heavy thunderstorm vs | tropical storm? It's still the same potentially life- | threatening and catastrophic event. | | [1] https://twitter.com/NWSNewYorkNY/status/14332773220486635 | 54/... | ijidak wrote: | It's never clear to me what to do with a flash flood | warning. | | Do I stay indoors? Do I move to higher ground? | | It can be a little vague as far as what should I do given | my exact location. | | I guess it's up to each individual to research those things | beforehand... | bogomipz wrote: | I believe the warning alerts advise not to travel unless | fleeing flooding and the flash flood emergency alerts | specifically state "move immediately to higher ground" | and "don't walk or drive through flood areas." | | One criticism I've read a few times in the past week has | been suggesting that people may have had alert fatigue. | While it is true that things like the Weather Channel | have contributed a lot of noise(naming winter storms for | instance.) Additionally there were 4 separate alerts that | went out the night of the flooding. And of course things | like Amber alerts and similar seem to be commonplace now | so there may be some truth to that. The irony however is | that as a society we seem increasingly more fixated on | our screens and don't mind the endless text messages and | social media and app notifications yet somehow | potentially life-saving alerts would be the source of | fatigue. | dnautics wrote: | People forget that "superstorm sandy" wasn't even a hurricane, | iirc it was a "tropical depression" by the time it got to nyc | beerandt wrote: | If you don't go through it, it must not be that bad. | | If you do go through it, it was worse than the category/ | windspeed/ storm surge numbers convey. | | "You just had to be there! It was way worse than just a | tropical depression!" | | It was the media experiencing this phenomenon that gave birth | to the hyperbolic term "Superstorm Sandy". | | Anyone who's actually been through a hurricane saw through it | right away. | selimthegrim wrote: | In other interviews the engineers claim the levees were built to | a 200-year level, and that a 100-year level would not have been | sufficient for Ida. | Filligree wrote: | If we get 100-year storms every five years, then is that really | the correct description? | throwawaysea wrote: | From the USGS page on 100 year floods | (https://www.usgs.gov/special-topic/water-science- | school/scie...): | | > 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. | | And it looks like these terms are based on past data not | future projections: | | > Since the 100-year flood level is statistically computed | using past, existing data, as more data comes in, the level | of the 100-year flood will change (especially if a huge flood | hits in the current year). As more data are collected, or | when a river basin is altered in a way that affects the flow | of water in the river, scientists re-evaluate the frequency | of flooding. | MisterBastahrd wrote: | The entire rest of the west bank parishes is still protected by | the "old" definition of a 100 year storm, and they had multiple | breeches this year. | ErikAugust wrote: | http://trimread.org/articles/1154 | yread wrote: | > Army Corps of Engineers, which rebuilt the system | | It's funny they don't mention the companies like Arcadis that | actually designed the barrier, because they have the know-how | from managing the Dutch flood barriers | | https://www.h2owaternetwerk.nl/h2o-actueel/beschermingssyste... | xxpor wrote: | Wow, someone in a US government (at any level) actually | consulted a foreign expert for something? And a non-Anglo | country at that? | | Can whoever was responsible please take over transit funding at | DOT? We need so much more of this. | koheripbal wrote: | US gov't contracts frequently go to non-US companies - and | non-US gov'ts contract US companies all the time. | | The global economy is, wait for it, global. | beerandt wrote: | With the political nature and extreme size of the project, | there weren't many engineering companies with a presence in SE | LA that didn't get a sizable contract out of it. | sixothree wrote: | There is plenty of good news from Louisiana. But mostly because | of the levees holding, the loss of life was low. ___________________________________________________________________ (page generated 2021-09-05 23:01 UTC)