5 ms·

> Katrina used to be a once-in-a-lifetime event, now hurricanes of similar size occur every few years I think this is patently false, although you're correct t

> Katrina used to be a once-in-a-lifetime event, now hurricanes of similar size occur every few years I think this is patently false, although you're correct that judging by news reports one might think otherwise. For some perspective on the relative damage of hurricanes over many years, this diagram [1] is pretty good. Katrina looks like a big statistical outlier to me. [1] https://www.scientificamerican.com/article/why-hurricane-names-are-retired/ https://www.scientificamerican.com/article/why-hurricane-nam...

dontreact 6y ago
This graph is great. It does make it seem like there is starting to be a trend of increased damage in terms of dollars. If we have another one causing 30+ billion dollars of damage this year, it looks to me like there will be a clear trend.
- hcrisp 6y ago
  More infrastructure being built by the coast would cause damages to go up, even if storm severity remained constant. Edit: Found an article which says just that. https://www.cnn.com/2018/09/12/us/hurricane-damage-cost-coast-development/index.html https://www.cnn.com/2018/09/12/us/hurricane-damage-cost-coas...
  - dontreact 6y ago
    That's a true statement. In the wider context of this conversation, I think it is important to emphasize that a big factor for continued development along the coasts despite an increasing trend in damage appears to be climate change denial From the article you posted: "But rather than adjust the state's plans for coastal development, the Republican-controlled legislature passed a law in 2012 that banned state and local agencies from using sea-level estimates that "include scenarios of accelerated rates of sea-level rise." The law required predictions to stick to historical trends, despite scientific evidence that sea levels are rising at an accelerated rate due to climate change."
JimboOmega 6y ago
As a lifetime weather nerd - I think if you could smooth the trend there would be a trend towards worse hurricanes, but there's huge variations from storm to storm and season to season. There is a slight trend towards more storms, and a trend towards more building on the coast or in vulnerable areas that increases damage. There's also a trend towards more news coverage of extreme weather. There are so many random factors though. Katrina was terrible because it hit New Orleans rather directly, which is an incredibly vulnerable (and high population) city, and the levees broke in conditions they should have been able to withstand. If that same storm hit Brownsville, TX, or Panama City, FL, people would have paid way less attention. If it hit Veracruz, MX, nobody in the US would remember it. Category-at-landfall is not a good indicator either. Winds get all the hype, but water does most of the damage - as it did in Katrina. While storm surge as driven by those winds is a factor, it really matters which ways the winds are blowing and how the waters pile up based on local geography. Rain is a huge factor too, so situations where a storm drifts inland and then parks are much worse than a storm that promptly races off. (Such conditions caused bad flooding in Houston recently). So exact landfall conditions matter, how fast a storm moves, etc. Storms may be a little stronger than they used to be but that says very little. People remember when we get unlucky and a major city gets hit in a very unlucky way, and that's always going to be mostly a random occurrence. Houston exists as a city because a hurricane destroyed Galveston. It still gets severe flooding from tropical storms, and has in recent memory. Like New Orleans, it's in a bad place (clearing out a swamp to build a city will always have this problem; the water wants to go where it did before). It will almost surely happen again. It's easy to play fearmonger, and imagine "worst case scenarios", but many of them have played out - Katrina, Sandy, Houston, etc. Even if the odds of those scenarios have increased from 1/100 to 1/50, there's no telling when the next one will happen; we could go 50 years without another one, or Miami could hit by a cat 5 in a month. It's still a stupid idea to invest in cities built in wetlands in areas vulnerable to hurricanes, but people keep doing it. Sea level rise makes this even stupider (more so than the storms getting stronger), but again, people keep doing it. A lot of people justify it because it hasn't happened in X years where they happen to live, but it is a numbers game, and sooner or later their number will come up.

dontreact 6y ago

This graph is great. It does make it seem like there is starting to be a trend of increased damage in terms of dollars. If we have another one causing 30+ billion dollars of damage this year, it looks to me like there will be a clear trend.

hcrisp 6y ago
More infrastructure being built by the coast would cause damages to go up, even if storm severity remained constant. Edit: Found an article which says just that. https://www.cnn.com/2018/09/12/us/hurricane-damage-cost-coast-development/index.html https://www.cnn.com/2018/09/12/us/hurricane-damage-cost-coas...
- dontreact 6y ago
  That's a true statement. In the wider context of this conversation, I think it is important to emphasize that a big factor for continued development along the coasts despite an increasing trend in damage appears to be climate change denial From the article you posted: "But rather than adjust the state's plans for coastal development, the Republican-controlled legislature passed a law in 2012 that banned state and local agencies from using sea-level estimates that "include scenarios of accelerated rates of sea-level rise." The law required predictions to stick to historical trends, despite scientific evidence that sea levels are rising at an accelerated rate due to climate change."

JimboOmega 6y ago

As a lifetime weather nerd - I think if you could smooth the trend there would be a trend towards worse hurricanes, but there's huge variations from storm to storm and season to season. There is a slight trend towards more storms, and a trend towards more building on the coast or in vulnerable areas that increases damage. There's also a trend towards more news coverage of extreme weather. There are so many random factors though. Katrina was terrible because it hit New Orleans rather directly, which is an incredibly vulnerable (and high population) city, and the levees broke in conditions they should have been able to withstand. If that same storm hit Brownsville, TX, or Panama City, FL, people would have paid way less attention. If it hit Veracruz, MX, nobody in the US would remember it. Category-at-landfall is not a good indicator either. Winds get all the hype, but water does most of the damage - as it did in Katrina. While storm surge as driven by those winds is a factor, it really matters which ways the winds are blowing and how the waters pile up based on local geography. Rain is a huge factor too, so situations where a storm drifts inland and then parks are much worse than a storm that promptly races off. (Such conditions caused bad flooding in Houston recently). So exact landfall conditions matter, how fast a storm moves, etc. Storms may be a little stronger than they used to be but that says very little. People remember when we get unlucky and a major city gets hit in a very unlucky way, and that's always going to be mostly a random occurrence. Houston exists as a city because a hurricane destroyed Galveston. It still gets severe flooding from tropical storms, and has in recent memory. Like New Orleans, it's in a bad place (clearing out a swamp to build a city will always have this problem; the water wants to go where it did before). It will almost surely happen again. It's easy to play fearmonger, and imagine "worst case scenarios", but many of them have played out - Katrina, Sandy, Houston, etc. Even if the odds of those scenarios have increased from 1/100 to 1/50, there's no telling when the next one will happen; we could go 50 years without another one, or Miami could hit by a cat 5 in a month. It's still a stupid idea to invest in cities built in wetlands in areas vulnerable to hurricanes, but people keep doing it. Sea level rise makes this even stupider (more so than the storms getting stronger), but again, people keep doing it. A lot of people justify it because it hasn't happened in X years where they happen to live, but it is a numbers game, and sooner or later their number will come up.