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Hurricane Ida could be close to Cat 4, dump up to 20“ of rain in S.E. Louisiana (nola.com)
123 points by lsllc on Aug 27, 2021 | hide | past | favorite | 153 comments



What some might not know is that New Orleans is currently extremely unprepared for a major hurricane. Some water pumps are offline, and the city is currently in the middle of a huge amount of road and infrastructure work. Flooding will likely be much worse for this storm than normal.

If you're in New Orleans, I recommend considering an evacuation if you have somewhere to go.


> What some might not know is that New Orleans is currently extremely unprepared for a major hurricane.

Honestly, I think it's a little incredible that someone might think they would be prepared. The city was woefully unprepared for Katrina, and the only cities I can think of that might have a more robust history of political corruption and wasted tax dollars are Chicago and Washington, D.C.. Of course nothing has changed and they're entirely unprepared for a hurricane.


You know, I have some hope. The Army Corps of Engineers is not what I would call a politically charged area of the government, and the costs, while substantial, are manageable for the work that needed to be done.

https://www.mvn.usace.army.mil/Portals/56/docs/PAO/Brochures...

"Following Hurricanes Katrina and Rita in 2005, the U.S. Army Corps of Engineers was authorized and funded to design and construct the Hurricane and Storm Damage Risk Reduction System for southeast Louisiana. The Corps strengthened and improved virtually all of the levees, floodwalls, pump stations and surge barriers that form the 133-mile Greater New Orleans perimeter system. The system that is in place now is stronger and more resilient than it has ever been in the area’s history. The new system is capable of defending against a 100-year level storm."

"The Hurricane and Storm Damage Risk Reduction System (HSDRRS) is fully funded at $14.45 B."

"Risk cannot totally be eliminated; everyone shares responsibility for buying down risk through insurance, zoning and building codes, coastal protection and restoration, and complying with mandatory evacuations." My emphasis on this last statement from the pamphlet I reference. Everyone is responsible for working together to derisk.

Lets see what that money bought.


Just a few days ago I went to Bound Brook, NJ as the river crested the highest it's been since 2005, at around 30.5ft on the gauges. This would have previously left most of the town, including its main street underwater as it famously did during hurricane Floyd. However this time it was totally dry due to improvements the Army Corps of Engineers completed in 2012. https://www.nan.usace.army.mil/Portals/37/docs/civilworks/pr...


I have photos from 1999 when all of bound brook and part of somerset was underwater. I was shocked how they completely absorbed the recent storm.

Also glad to see central NJ represented on HN!


The Katrina scenario was predicted years in advance and nobody did anything to protect the city.


The engineering work I described in my top post proved successful during this most recent hurricane (Ida).

https://www.bloomberg.com/news/articles/2021-08-30/new-orlea...


I think this is a little bit unfair. New Orleans has an incredible amount of infrastructure to prevent flooding compared to pretty much any other coastal city. Spillways, levees, giant pumps, etc. Even if it fails, you can't really claim that they are "entirely unprepared for a hurricane". At this particular moment, though, some of that infrastructure is weaker than normal.

They definitely have corrupt politicians though, no doubt about that.


Most of New Orleans can happily drain what would put Houston under 6 feet of water.

And no amount of drainage can do much when you are on the east side of a powerful storm. You can have pipes from here to the moon but there's nowhere for that water to go. Storm surge is concerning to the people in the know for a reason.


I lived in New Orleans for 24 years and personally went through Katrina - so I actually consider one of the people in the know. I still think New Orleans has done its share of preparation. Enough? Not sure. But it's not like New Orleans is ignorant of how to prepare their city for a hurricane.


Yeah, I spent my birthday sleeping in a neighbor's gun closet after Katrina because he had AC in his apartment above his garage. LOL.


The 20" of rain isn't nearly as scary as the 11 foot storm surge that is possible.


A storm dumping rain over the Mississippi drainage for 3--4 days is somewhat more fearsome than 20" in one spot for a few hours.

All of that flows out through the Mississippi.

I'm not saying it's worse than the storm surge. But it's going to be affecting the city for much longer. (As well as multiple locatons upstream.)


Chicago pretty easily unburied itself out of two major snowstorms and extreme (even by normal standards) cold snaps. At least when it comes to the extreme weather the city faces, that part is handled.

General corruption/waste is another matter. Recycling in Chicago right now is notably inefficient, for example (something like a 9% clearance rate).


> Chicago pretty easily unburied itself out of two major snowstorms and extreme (even by normal standards) cold snaps. At least when it comes to the extreme weather the city faces, that part is handled.

That's not really the question, though. The question is if you'd be surprised if they didn't.

I wouldn't be that surprised to hear that Chicago was unable to clear snow from a 100-year snow event because the funds were mismanaged or something similar. That sounds entirely within character.

I wasn't surprised when I heard about the ongoing problems with the Texas power grid, either. I was horrified by the deaths, of course, but did it surprise me that an for-profit utility market didn't result in a robust infrastructure? No. Infrastructure and utilities don't work well under those sort of economic pressures. I wasn't surprised it was fragile.


> I wouldn't be that surprised to hear that Chicago was unable to clear snow from a 100-year snow event because the funds were mismanaged or something similar. That sounds entirely within character.

Former Mayor Michael Bilandic famously lost reelection in 1979 after botching snow removal following the large blizzard of that same year. Ever since, snow removal has been one of the city government's core competencies; even the quite intense Groundhog Day blizzard of 2011 was well-handled, though it managed to shut down LSD for a bit. There's plenty of mismanagement and corruption in city government to go around (the police department is famously corrupt and incompetent and shows no signs of turning that around), but snow removal is one thing that can generally be counted on here.


Weather forecasting today is also much better than it was in the 1970s. The Blizzard of '78 in especially the Boston area would still be bad and the city might even still be largely shut down for a bit, but you probably wouldn't have the spectacle of mass evacuation from cars on Route 128 because the highway had literally ground to a complete halt.


They actually studied the cause of Lake Shore Drive shutting down in the blizzard and found that it was because of a cascading series of cars and busses got stuck, preventing plows from reaching sections of the road. So they built removable median sections in strategic locations that allow snow plows to bypass traffic snarls and free up the road again.


> I wouldn't be that surprised to hear that Chicago was unable to clear snow from a 100-year snow event because the funds were mismanaged or something similar. That sounds entirely within character.

I guess if you’ve never lived near Chicago or visited in the winter, that might be reasonable. But they take snow extremely seriously. Like so seriously it’s funny. It truly is. The “mismanagement of funds” is true - they spend a lot of money on snow management.

They have over 200 snowplows, and every single garbage truck has a plow attachment so it can be put into plowing service, most of the city pickup truck fleet as well, etc.

[1] > Department of Streets & Sanitation (DSS) coordinates Chicago's snow and ice control efforts from Snow Command. This high tech command center allows us to access and view a network of cameras and pavement sensors to get a quick and accurate assessment of our pavement conditions citywide. We track incoming weather systems via Doppler radar and through constant communication with our meteorological consultants and the National Weather Service. And we combine all of these technologies along with the Global Positioning Systems (GPS) on all of our trucks to strategically deploy our snow personnel to up to over 280 snow routes.

People used to claim that the streets that alderman lived on got plowed first whenever it snowed, so the city put GPS on everything and built a plow tracking website, so you can see where everything is in realtime, any time it snows. [2]

[1] https://www.chicago.gov/city/en/depts/streets/provdrs/street...

[2] https://www.chicago.gov/city/en/depts/streets/supp_info/plow...


Not to mention that unfunded pensions are an Illinois speciality these days.


Katrina was a cat 5. It was also the fourth-most intense Atlantic hurricane on record to make landfall in the contiguous United States.

https://en.m.wikipedia.org/wiki/Hurricane_Katrina


Katrina was not a cat 5 when it made landfall


It was a category 3 when it made landfall in Louisiana as stated in the article the OP linked.


The problem with being prepared for tropical storms in the gulf is that it takes a few days to get prepared, get people evacuated... But 'a few days' isn't enough time for hurricane forecasters to reliably predict where a storm will make landfall, and how strong that storm is going to be. (Sheltering in place against a small storm, that your infrastructure is built to handle is the correct play.)

Not to downplay the corruption problem, but if the gulf states prepared for every incoming storm, they'd be in a constant state of evacuation, and nobody would get anything done during hurricane season.

Oh, and evacuations kill people in themselves (Car accidents, the sick and infirm, etc, etc). Do too many false alarm evacuations, and you'll kill more people than the storms would have.


>Oh, and evacuations kill people in themselves (Car accidents, the sick and infirm, etc, etc). Do too many false alarm evacuations, and you'll kill more people than the storms would have.

I can vouch for this. Deadlocked roads with cars with nowhere to go in the middle of summer heat for hours or even days on end. Limited gas, limited food and water, no proper medical care. Not a safe environment. Evacuations aren't in any way risk free.

https://www.researchgate.net/publication/270472303_Deaths_re...

There were 111 deaths related to Hurricane Rita in the state of Texas. The three direct deaths were from wind blown trees. A majority of the deaths (90/108 or 83.3%) were related to the mass evacuation process.


If there is so much uncertainty in living there, why do people keep rebuilding in the same spot?


National Flood Insurance Program and other subsidies.

Private insurance rates should increase and drive out residents. Business losses should drive out both business and residents.

Without subsidies, I suspect the market would increase the COL such that it would lower the population.


After $14,000,000,000 was spent, they had better be ready


What is Uber's valuation?


Heh yeah in my experience the only thing New Orleans is well prepared for is parties and debauchery. Not that there’s anything wrong with that :)


I live in a part of town affected by one of the pump outages. In any other city in the country this would be shocking and whatnot. Here it’s an opportunity to lampoon the local government because that’s all we have.


It's also just false outrage generated by media that wants to shock readers.

The reality is that, from the article...

>Other nearby stations are expected to have enough capacity to pick up the slack

At the individual pump level...

> 96 out of the S&WB’s 99 main drainage pumps are ready for Ida.


I’d imagine being prepared will be harder and harder to do each year as climate change means longer/worse hurricane seasons.

The reality is there will always be rain/winds/damage from hurricanes, but how is a place supposed to be ready for another Katrina every couple years now?

It sounds like a constant state of disaster-rebuilding-disaster-rebuilding…


Why? The pumps are not used a majority of the time. They are only needed when it rains.

They are usually not working, so maintenance should be easy.

...which it is because 96 of the 99 pumps are currently operational.


Crazy idea: instead of rebuilding, move. If this is happening every 15 years, maybe that's a message that we should be listening to. Somebody else said that if we evacuated every time a hurricane threatened, we'd be evacuated half the year. Sounds half right!


Also move away from: California - earthquakes, wildfires, draught, PNW - fires, complete snow in, barren eastern side of states, the entire gulf coast, the entire eastern seaboard, the City of New York, anywhere there's ever been an EF5 tornado (most of the 'midwest' i guess?) ...


Naive question: Isn’t it possible to plan those things when it’s not hurricane season?


Hahahaha no, the pumps are barely at capacity for a storm right now because half of them are like 100 years old and take a really weird voltage that can only be supplied by the Sewerage & Water Board's generators. One of which has been waiting on repairs since like last summer. I can't recall the exact reasons it's taking so long, I know it's a combination of "barely anyone even knows how to make the replacement part", "city's broke", and waves vaguely at all the supply chain mess caused by covid.

(One of our major industries is tourism, though a lot of that money gets siphoned off to the pockets of the tourist board. Mardi Gras 2020 was the last gasp of that before covid. We normally have a shit-ton of festivals all year round that draw people in to spend money. They've all been cancelled.)

And the roads are always sinking, the city's built on swamp. There will never be a time where the roads (or something under them) do not need maintenance. I'm sure the money crunch ain't helping that get done in a sane timeframe either. Also "hurricane season" is like half the year normally, and the past several years have had it well underway in the preceding month.


>really weird voltage

No- voltage would be easy to change with a transformer.

It's that many pumps run on 25hz, not the 60hz of the power grid.

They have to change frequencies via mechanical methods (motor-gearing-generator) or generate their own power via on-site turbines.


Also should add- this wasn't the result of a bad design choice.

It's because many of these pumps are literally older than the electricity grid.


They wanted to make sure the FEMA money wasn't stolen. I don't blame them.


Yes, just how you plan construction on existing infrastructure that can't be "turned off". You should at least not make what exists worse.


Not-hurricane season is the winter, difficult for construction, though I don't know exactly about that far south.


Winter in Louisiana is nice and balmy, we northerners would not call that winter. Above freezing, no snow. Much better conditions for manual labour than the summer there tbh.


Ok, fair enough. A lot of civil planning uses really long tail distributions for temp and so on, so I still wonder when stuff is schedulable.


haha, it does freeze, for days at a time. It hard freezes for at least 2 days, this past winter it hard froze for nearly a week. You may have heard about that in the news, because Texas went offline. Louisiana fared better in the grid area, but we still have rough winters, depending on the year. It's snowed thrice in the past 6 years, too.


"Not-hurricane" season extends from November through May, and potentially into June, in terms of low likelihoods of storms. As others note, Louisiana winters are exceptionally mild, and are generally preferable to summers for outdoor activity.

Late August / early September, by marked contrast, is peak hurricane season.


Winter is the wetter season.

Which most people don't realize, because it also rains so much in the summer. But it's so hot in the summer, that evaporation out paces the rain.

The driest months are Sept-Oct, which is peak hurricane season.


> Some water pumps are offline, and the city is currently in the middle of a huge amount of road and infrastructure work.

Why?


Some context: https://www.nola.com/news/hurricane/article_2f508a9e-06b8-11...

Sounds like turbine failures?


Turbine failures, lack of redundancy, 100 year old equipment with no supply chain.


Here’s a link regarding the pump outages https://www.nola.com/news/hurricane/article_2f508a9e-06b8-11...


> Other nearby stations are expected to have enough capacity to pick up the slack

This post seems like fearmongering. Out of 24 pumping station, one is out, two are at partial capacity, and the other 21 are working at full capacity.

At the individual pump level...

> 96 out of the S&WB’s 99 main drainage pumps are ready for Ida.


Most people I know here are staying at present. If it is Cat 4+ that might change.


This is what I hate about the category system - it's entirely wind based and while that's important, rainfall and direction of wind (for coasts) is what's most important. Cat 2 can be worse than Cat5 also because they move slower so more inches of rain per hour.


Interestingly, the Enhanced Fujita scale (EF) used for tornadoes takes into account damage as well as wind speed. Maybe something like that would be more appropriate for hurricanes. An 'enhanced' saffir-simpson scale?

https://www.weather.gov/oun/efscale


It already does. There's no problem with the system, for people that understand what it is meant to describe. Rainfall isn't a part of that.

The best way to describe rainfall is by... giving the rates and cumulative amount of rainfall. Flash flood warnings exist when excessive rain causes... flash flooding.

As for direction: hurricanes are circles. Everyone knows the east eyewall is the worst part.

Idk what else you'd want to incorporate/describe that's useful. Except that people that haven't been through bad hurricanes always think what they experience must be worse than the category of the storm.

Eg: Sandy not being hurricane strength when it came ashore, so they made up the term "Superstorm Sandy" because "just" tropical storm somehow lessons their experience.


>It already does. There's no problem with the system, for people that understand what it is meant to describe. Rainfall isn't a part of that.

I wasn't necessarily saying there was a problem with the system. However, when these terms/systems are used in the primary means of communicating dangers to the public (mass media: tv, radio, web) then they are doing a disservice. For a layman, the only difference between a cat 4 and a cat 5 hurricane is that the cat 5 is worse. Yet, for different areas, the category doesn't actually speak of the dangers. And, you risk people thinking "oh, I was in a category 4 before" and not realizing the potential of a 'lower' storm depending on the conditions.

I think the recent flooding in NY from the remnants of Hurricane Ida speak to that.


damn, Cat 3 is enough to make South Floridians evac north and that doesn't cause nearly as much flooding as places like New Orleans or TX. They really should evac...


Update: they are mostly leaving now.


New Orleans is almost below sea level. I'm not sure how much good all the preparation would do even if it did get done.


Most of New Orleans is literally below sea level.


Ain't no "almost" about it, most of the city's like 5' below. It's still been there for more than 300 years. The effort put into levees and pumps has been heroic.


The levees are sinking too.


everything's sinking


Ask the Netherlands that question.


You know what's fucked up; the USA.

Recall the student that built a detailed map of critical telco infra and was censured by the Gov because it contained "secret" infa info even though it was all from public record.

Infra is a joke in the US. Pay attention to whom the funds go from the infra bill...

Especially on the micro level: recall that MANY Congress officials wives created LLCs during the TARP 2008 "bailout" to receive funds with no consequence.

We are seeing the same.

We need a live update on budget appropriations


Love the downvotes, either by compliant or other:

Senators wives were caught creating LLC "foundations" to funnel money from the bailouts to their fake orgs.

It happens, does happen and will continue to happen.


It's off-topic, and complaining about votes is against the HN guidelines.

https://news.ycombinator.com/newsguidelines.html


[flagged]


This username was created 10 months ago. Please don't make false assumptions (I have another username that is older than yours), please don't use ad hominem arguments, and please help by doing your part to keep HN a nice place.


Vote out the incumbent every time is the only strategy I can think of. If you vote in an honest person, which is unlikely, the system will likely corrupt them after a year or two.


"Tropical Storm Ida could be close to Category 4 hurricane strength when it makes landfall Sunday on Louisiana's coast"

"Sunday is the 16th anniversary of Hurricane Katrina."


Having Hurricanes reach maximum average strength about the same time every year isn't that big of a surprise.


Oof.


It's not a huge coincidence, because it's hurricane season. There's a graph here, under "Number of Tropical Cyclones per 100 Years": https://www.nhc.noaa.gov/climo/


Look at a fancy view of the current forecast and other data here:

https://cwcgom.aoml.noaa.gov/cgom/OceanViewer/index_phod.htm...

edit: the sea surface temps are nuts


> the sea surface temps are nuts

Can you imagine what these temps will look like if the Gulf Stream slows/shuts downs as predicted?


Can you expand on that a bit, I don't have any context to understand how far out of whack it is?


It’s a almost as bad as it could be. The only thing that could make this worse is of the hurricane slowed down over the gulf and stayed there for a couple days.


Wow, hadn't seen this before. Thanks for posting it.


here is a satellite view I've been watching, also from NOAA:

https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G1...


That's the geostationary view of the gulf.

Here's the "floater" that stays overhead of the storm as it comes ashore:

https://www.star.nesdis.noaa.gov/goes/floater.php?stormid=AL...


Good thing southern hospitals have a lot of space for casualties right now.. .


Yeah it is potentially a really bad situation right now in Louisiana. We have been getting our vax numbers up recently and the hospitalizations have started to come down in the past week or so, but not by much.

With catastrophic hurricanes, though, what I've noticed is that we have lots of refugees (and deaths, in the case of Katrina) compared to hospitalizations. New Orleans can also turn the large arena areas (e.g. Superdome, Zephyr Field) into mass casualty and refugee areas immediately following the storm, which should help with keeping the hospitals from getting overrun.


The problem with refugees is crowding, displacement, lack of resources, and lack of communications.

These tend to exacerbate any extant public health situations. Given general incompetence concerning Covid in the Southern US generally, I've certain concerns.

What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota, then radiated outwards, toward the coasts and south, over the course of the winter, peaking around 10 Januare 2021. I've speculated that mass events, travel, return to school, and greater indoor activity (heating season in the north, as opposed to cooling season in the south) also contributed.

This year the US might se a dual hotspot originating in Sturgis and Louisiana, both radiating outward.

Something to keep tabs on.


> What was seen in 2020 was a winter wave which kicked off with Sturgis in South Dakota

Is there any actual evidence for this?


https://www.cdc.gov/mmwr/volumes/69/wr/mm6947e1.htm

Contact tracing + whole genomic sequencing proves that these infections in Minnesota came from the Rally, despite those individuals never attending the rally.

Those individuals then passed COVID19 to others in Minnesota. Etc. etc.


That's a pretty far cry from "the winter wave started at Sturgis."

> Following a 10-day motorcycle rally in South Dakota attended by approximately 460,000 persons, 51 confirmed primary event-associated cases, 21 secondary cases, and five tertiary cases were identified in Minnesota residents.

That's a drop in the bucket compared to the community spread in the US in 2020.

I'm not saying Sturgis was a great idea, but I am saying that the winter wave would have happened regardless.


I was going to make a similar comment, after having drawn the association above.

What the study does show is that the Sturgis variant was epidemiologically detectable throughout Minnesota following the rally. Note that the total number of samples was drawn from identified interviewed patients only, though this appears to have covered all reported cases in MN during the period (August 1 -- August 31, 2021). My understanding is that the survey was as comprehensive as could be achieved, and not a limited sampling.

During the same period, the 7-day average new-daily-case rate in Minnesota was 699--795 (rising slightly over the course of the month, observed from Worldometers). The Sturgis-linked cases were 0.4% or less of total confirmed cases.

(I'm assuming the CDC tracing was comprehensive, the paper is less than clear on this, though that appears to be the case.)

We could make numerous arguments that the study was flawed, missed cases, was incomplete, etc. All of that would be an argumment from ignorance. And though I feel there's some case to be made for suggesting the CDC undercounted, that leaves us with a weak basis for any further conclusions. Sometimes, though, in epidemiology, that's the best that can be done, and the precautionary principle kicks in: what course of action would provide the maximum benefit and least harm.

Minnesota's Winter Wave really started spiking in October of 2020. It peaked on 20 November at 7,023 NDC (7-day average). Whether or not those cases are linked to Sturgis would require sequencing of a sample and drawing inferences.

That said ...

... other evidence comes from looking at the spread of Covid-19 hot-spots throughout the US from August -- January of 2020--2021. And that did show the radiating pattern I described. I'm not certain it's associated with Sturgis, but it very much walks like a duck.


That study wasn't about finding all the cases that originated from the rally. That was just proving that in fact, people who never attended the rally got sick with the same genomic-markers as the COVID19 present at the rally.

Which means that the "spread" of COVID19 from Sturgis -> Minnesota cannot be denied.

-------

http://ftp.iza.org/dp13670.pdf

Page 60 (Appendix 5) shows a nice graph showing the "trendline" of COVID19 cases ("synthetic Meade county"), vs Actual Meade county.

We can see that COVID19 cases spiked pretty hard after the Sturgis rally. Now maybe there was some "other" superspreading event happening in that area at the same time... but Occam's Razor points to the giant 400,000+ person motorcycle rally without any mask precautions going on.

---------

> That's a drop in the bucket compared to the community spread in the US in 2020.

But you're right on this front. I think the poster earlier is overstating Sturgis's importance. Sturgis is just one event, there were plenty of others with far bigger spread (February 2020 Marti Gras New Orleans, especially because no one took any precautions during that event. It was "before COVID19" was well recognized by the public)

But without a doubt, Sturgis was a superspreading event. But there were _many_ superspreading events happening all over the place, so I personally don't want to put too much importance on Sturgis alone. The fact remains that many other events continued to take place, as that region didn't want to take precautions against COVID19 in general.


I've read through the study pretty carefully, and it does appear to have tried to be comprehensive. Specifically:

All confirmed cases among Minnesota residents were reported to MDH. MDH or local public health department staff members interviewed patients with confirmed SARS-CoV-2 infection to identify exposures and persons who might have been in contact with patients during their infectious period (2 days before through 10 days after symptom onset).* To assess exposures, interviews included questions about travel and being in specific settings, such as bars or restaurants, schools, health care facilities, or events or social gatherings in the 14 days before symptom onset. During August–September 2020, MDH and local health department staff members interviewed >80% of patients with a confirmed SARS-CoV-2 infection.

If the survey missed cases, it wasn't for lack of trying. That's not to say it didn't miss some.

(Keep in mind I'm the person who'd suggested the relationship above.)


Orleans Parish itself has been tough on COVID. I feel like you're belling the wrong cat here.


Louisiana as a whole has not.

And however good Orleans Parish has been, that efficacy is likely to get a whole lot worse come Sunday.


I don't remember there being huge surges after Laura and whatever the one in october was, in 2020. I might be misremembering, but the primary issue was the incredible heat, and lack of water, radio, power, ice, food, etc. In the coastal regions they suffered for weeks - we only had a rough go of it for 3 days where i'm at, and it hit us Cat 3, plus tornadoes.


Clearly it's a case of "we'll have to see".

That said:

- There's a clear risk.

- Taking measures against the risk would be highly advisable.

- Monitoring the aftereffects, over several months at least, is going to be necessary to draw conclusions.

I'd also like to see a compilation of Covid (or other epidemics) and the interrelationship with other widespread disasters or disturbances. The situation in Afghanistan would be one such case, where there's a sudden breakdown of what limited order did previously exist. Wildfire evacuations in the Pacific Northwest of the US & Canada would be another. There's the long slow emergency of homelessness in California (about 100,000 individuals on any given day, not sure how many are long-term or not).



https://www.windy.com/-Rain-accumulation-rainAccu?rainAccu,3...

Click on "Next 10 Days" near the bottom.

Windy users know about this stuff way farther in advance.


Windy is an excellent graphical interface, but as I understand it, this forecast is a re-packaging of the ECMWF one (https://apps.ecmwf.int/webapps/opencharts). The GFS forecast (from the National Weather Service) also gets a similar track for Ida.


"People who look at forecast maps" know about this stuff way further in advance, surely.

That said, Windy is very good.


Windy makes a compelling visualization of data that is often totally wrong and misleading. Their presentation of PM2.5 concentrations in California right now is very pretty and also off by about an order of magnitude versus actual sensor readings. I will continue to prefer the much uglier but correct presentations from NOAA themselves, or the incredibly slow but rich and accurate data from wunderground.


"People who look at forecast maps" are way more confused about the weather actually happening than those that don't. FTFY ;-)

My local forecasts have predicted rain for multiple days in a row, and then those days arrive to sunny skies. The same day forecasts get updated to reflect the lack of rain, and then mid-to-late afternoon storms after zero prediction of them. This summer has been a bad luck streak for forecasters.


This isn’t the best advice, unfortunately. The best advice is to follow https://www.nhc.noaa.gov and your local NWS. Model forecasts are surprisingly unreliable and each model has its own biases, which is why the job of weather forecaster still isn’t automated. NHC has arguably the best tropical system forecasters in the world and their products are publicly accessible for all. Follow them first and foremost.


To be fair, I check a number of different forecast sites (including Windy) and follow a lot of different weather bloggers but no one knew this storm was a thing until a few days ago. And all of the models had it as a Cat 2 until yesterday.


Another endorsement of Windy. In 2017 Windy knew that Hurricane Harvey was going to stall out over SE Texas days in advance.


Windy doesn’t make forecasts, rather it visualizes output from forecast models.


Yup. You can even choose different models for it to visualize!


I've been following the storm via Nullschool and its forecast model (GFS).

Landfall of the eye has shifted about 40km westward, been delayed by about 6+ hours relative to the forecast 18 hours ago, and increased in intensity.

The green circle here represents where the eyewall landfall was previously forecast to occur at about noon CST. Current forecast shows landfall at Jack Stout Bay, south of Morgan City, and tracking about 40km west of New Orleans proper.

The area of landfall has been hit by several storms in the past several years, is mostly smaller settlements, and there are probably numerous already-damaged or only partially-repaired structures.

https://earth.nullschool.net/#2021/08/29/1700Z/wind/surface/...


The problem is that the eye is not the most damaging part, it's the right side of the eye that's funneling water from the Gulf onto the land that's got the most damage potential. From that link it looks like New Orleans is in a much worse situation than if it were to receive a direct hit.


There's that.

A near-westward hit could be more damaging than a direct strike, largely based on storm surge and possibly wind speeds.

What the maximal high-damage offset distance is I don't know, though 20--40km seems sufficiently close to be bad. I'd suspect a little nearer would be worse.

And I do wonder just how many more storms Nawlins and the Old River Structure have in them.


Whoa! This site is rad! I often thought about making something like this. It always seems like the for-pay weather apps are crap but all the data is freely available.



For the interested, real-time data from the ongoing aircraft reconnaissance into (now) Hurricane Ida can be seen at https://www.tropicaltidbits.com/recon


tropicaltisbits.com also hosts the author’s blog which is well worth following when major storms are present near the GOM.


I live in Louisiana, and attended Tulane for a while. Some streets around Tulane floods after a few hours of rain. I hope that every who lives in NOLA or high risk areas just goes ahead and leaves for right now. Some people tried to stay and party during Katrina. Hopefully folks don't make the same mistake twice...


The gulf is HOT right now. And that heat goes pretty deep.

I wonder if we'll see a Michael situation, where Ida just continues to intensify as it closes in on land.


SSTs are 30-32°C (86-90°F) in the GoM right now:

https://ocean.weather.gov/Loops/SST_GMex_SST/image_202108270...


Sea Surface Temperature

I'm sorry, you're saying the ocean surface is hotter than a heated pool right now? What is the baseline?


Pretty much. A couple of summers ago I stayed for a late August weekend at Hilton Head S.C. and going into the ocean was like getting into a hot tub. It was actually too warm, not at all refreshing from the 100+F day -- the Hotel pool was much cooler.

It was really eye-opening actually.


https://www.aoml.noaa.gov/phod/regsatprod/gom/sst_ts.php

~26C mean ranging from 23C in February to 30C in August.


Nullschool's SSTA (sea surface temperature anomaly) gives a good idea. Looks like +1.9C for the northern Gulf.

Note the cooler temps in Ida's wake. Hurricanes pump heat from the ocean to the atmosphere.

https://earth.nullschool.net/#2021/08/25/1200Z/ocean/primary...

(Time-pinned to an hour ago.)


It's not unusual for this time of the year. The thing to look at is SSTA (sea surface temperature anomaly), that will tell you how much the current temperature is deviating from the long term average for this month.

https://earth.nullschool.net/#current/ocean/primary/waves/ov...


The GoM gets pretty warm (I live on the water just off the GoM proper (Boca Ciega Bay)). Late summer temps in the upper 80s or low 90s are common. Our pool used to heat to 95 before the shade palms grew up.

I Don think I can recall the surface temp being less than 80 often, based on the data from my depth sonar on the boat at random times during the ‘winter’.


Isn't that precisely what the model shows it doing?


I am collecting data on this storm using barometers in Android devices with All Clear Weather:

https://play.google.com/store/apps/details?id=com.allclearwe...

If you want to join, you can download the app and go to Settings->Sensors to enable.

Here's an animation I made of Hurricane Dorian a couple years ago as it approached the coast of Florida: https://www.allclearweather.com/hurricane-dorian

And of course, there are recent scientific papers showing that this kind of data (barometric pressure from phones) could be useful in general weather forecasting to improve accuracy:

Smartphone Pressure Collection and Bias Correction Using Machine Learning: https://journals.ametsoc.org/doi/full/10.1175/JTECH-D-17-009...

Impacts of Assimilating Smartphone Pressure Observations on Forecast Skill during Two Case Studies in the Pacific Northwest: https://journals.ametsoc.org/doi/full/10.1175/WAF-D-18-0085....


Genuine question since I don’t live in a city which experiences severe weather events annually: what is the financial incentive in rebuilding destroyed homes, businesses and other infrastructure every few years? Does that actually lead to a net positive outcome for those affected in the long run?


Find a map of the rivers that drain into the Mississippi. Think about how much shipping still happens on the rivers, despite the highway and train networks. Lots of goods pass through there, which means lots of money flows through (and all too little of it sticks).

New Orleans is the least shitty place to put a port on the Mississippi. Or at least it's been that since its founding. Rising sea levels and "hundred-year storms" becoming "twenty-year storms" may change that.

And also... it's home. I grew up there, left for a while, came back right before Katrina, and leaving after that ripped a chunk of my heart out that I've only started growing back after returning a couple years ago. The place is fucking magical for the 347 days out of the year we're not staring down a hurricane that might be aimed right for us. Most of them see us staring and decide to go elsewhere.


It's crazy to me how discussions, especially on HN, about some place being less livable always produce comments to the effect of "why wouldn't they just move." Family, friends and history are a tight tie. Probably the tightest and most human tie. Extremely understandable.


I don’t think anyone suggested moving, certainly not me. I’m not from the US and have no idea how these annual hurricanes affect the south west, hence my question.


I'm not saying some areas don't suffer huge losses and this might be a bit of survivorship bias, but living in Miami for 35 years, homes built from cinderblock with roofs secured with hurricane straps -- which have been part of the building code for 30+ years now -- don't really see much damage other than the odd missing roof tile and maybe a bit of water intrusion from the wind, but it's not as dramatic as the media portrays it in _most_ areas.

I'd say the major threats are fallen power lines, downed trees, and CO poisoning from generator misuse. We'll get routine summer monsoons that bring more damage than some category 1 hurricanes at times, so unless it's a direct hit from a major hurricane I try not to panic too much so long as we have supplies.


also popular to clear out trees close to the house. some people make the rookie mistake of not doing that and end up with an open roof during the storm.


Most of the time it isn't the same places that get hit. Its not as if the same neighborhood is rebuilt year after year, many of these places have homes and infrastructure that is 100 years old.

Also keep in mind that a majority of the East Coast is under threat from Hurricanes. If we just abandoned any area that has been severely damaged by a hurricane, there would effectively be an unpopulated coastline from Boston to the Mexican border.


There are steps between doing nothing and abandoning the east coast. There are some areas (right at sea level, river flood zones) which probably are better off as parks, and letting things like costal mangrove forests regrow would be important, but there’s a lot of places where a significant fraction of the existing buildings could remain viable if they were sensibly built following good design practice rather than as cheaply as the developers could get away with.

It seems like something flood insurance and building codes should get increasingly stringent about, similar to how some California fire codes started requiring houses to be built to support sheltering in place during wildfires so you didn’t have so many people evacuating and needing to rebuild as many homes. It’d be nice if that started as guaranteed annual premium increases for unsafe properties with an assistance program for primary residences which phases out based on property value.


The wealth of a society isn’t in houses and TVs. It’s institutions and structures, such as companies, clubs, families, universities etc.

That’s how you can almost literally wipe a city off the face of the earth and see it rebuilt within a decade, think Germany after WW2or London/SF/Chicago after fire and earthquakes.


Or NOLA after the Great Fire of 1788, or NOLA after Katrina. :)


There's something special about New Orleans. It's worth it all.


"I live in a city which does not yet experience severe weather events annually". FTFY.


Moral hazard has entered the chat.



Houston dodging more bullets than Neo in the matrix. I'm glad but feel bad for our neighbors.


I mean, we DID get Harvey.

My lay take here is that the flow of the Gulf Stream tends to bend the storms to the east as they approach the coast, so you get these curveball tracks that, unfortunately, disproportionately seem to smack Louisiana and Mississippi.

Harvey came ashore further south, and so the eastward movement caught us (though that's a gross oversimplification of Harvey's actual mechanics).


Yeah but Harvey was mostly rain. If we had a category 5 go up the ship channel the entire US would be impacted. So much oil, fuel, etc goes through here.


Fair. I was just thinking in terms of local impact.


If I remember correctly, he only successfully dodged 2/3 bullets. And then he started to stopping them


Louisiana is just going to lose so much territory between now and the end of the century to the ocean. Their shorelines are just too shallow to deal with the hurricanes and rising sea levels that are coming.



There's nothing to be happy about when a hurricane is bearing down on you, and it's worse when you're caught on the east side of the storm with heavy rains because the winds blow counter clockwise, meaning that rivers and streams and lakes that open or drain into the Gulf of Mexico will pile up and keep getting higher as long as the story is over the area. Southeast Louisiana can take 20 inches of rain over a few days, but not when there's no place for the water to go.


The National Hurricane Center has updated the forecast for Ida and now calls for it to be a 140 MPH Cat 4 (or greater) at landfall. The previous forecast had Ida topping out as a 120 MPH Cat 3. Storm surge of 10 to 15 feet above ground level will impact a broad area.

https://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/271449...


Well I hope the trucker motels in West Memphis aren't full.


How does this 20" of rain compare to Katrina? https://svs.gsfc.nasa.gov/3221


Hurricane Katrina saw 15" of rain over New Orleans in 2005, though a higher storm surge was measured (14') than what is predicted for Ida (7--11').

https://en.wikipedia.org/wiki/Hurricane_Katrina

http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf [pdf]

There are multiple factors that come into play.

There's storm surge and tides. Tides around Morgan City are pretty modest (less than 1/2 foot / 15cm total range), and will be low as the storm arrives. Storm surge forcast is 7-11 ft per NOAA. Given the extreme low-lying land, that's significant. I don't have comparative numbers for Katrina offhand.

The total rainfall amount is one. The period of time over which it falls, and where the storm goes afterward are also critical. Ida looks to be slow-moving, and is presently slated to track pretty much directly up the Mississippi river, then over the Ohio River Valley.

That means there's going to be heavy river flow coming downstream possibly for several weeks after the storm itself passes. I'd predicted and observed a similar trend when Hurricane Florence hit Wilmington, NC, in 2018, and upstream-based water flows contributed to flooding, and issues such as hog farm sludge empoundments (basically: pig shit lakes) in the region. For Louisiana, the concern is probably more petroleum refining and chemical plants.

Note that Florence hung around for days. Ida looks as if it will stick around Southern Louisiana for about 18 hours, then start accelerating to the NNE, though remaining over the drainage baisin feeding into New Orleans.


I don't know but the scale of that viz only goes to 80mm, which is only 3 inches.

The forecast for the river in New Orleans suggest no flooding this week.

https://water.weather.gov/ahps2/hydrograph.php?wfo=lix&gage=...


There's still flooding from last week's storm in TN...


They found the last person yesterday: https://abcnews.go.com/US/wireStory/fema-administrator-tours...

The word is that the railroad embankment acted as a temporary levee and stored a large charge of water up, until it failed. Then this impromptu lake charged right through town. It's usual for that are to flood, this was just a lot more water all at one time than usual.

There were pictures of cars filled with gravel; and that rail berm blown completely out, tracks dangling.




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