Hurricane Return Periods by Locale

[mempho]

Two threads today have dealt with hurricane return periods...these periods are viewable on maps at http://nhc.boulder.noaa.gov/HAW2/english/basics/return_printer.shtml

I have linked Cat 3, 4, and 5 return periods for the southeast and gulf coast of the U.S. These return periods are not nearly as common as some people here want to believe nor are they as rare as some people want to believe. For instance, I don't think we saw a storm that was a once in 500 year event last year. One caveat to these maps: These maps show the return period for a hurricane of the given intensity passing within 75 nautical miles of the point shown on the map. These may or may not implicate actual landfall intensities and the researchers are probably working with an insufficient dataset, so caveat emptor!

So, here we go (Notice that the worst place for hurricanes is also one of the most highly populated):

Category 5




Category 4



Category 3



You can view this for the entire east coast and for all categories by using the link at the beginning of the post.

[all_we_know_is_FALLING]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

[Anonymous]

Hey mempho, thanks for finding these links/maps! I find it interesting that a Cat 5 passing within 75 miles of NYC is a once in a 370 year event. If the average was to hold true, we don't have that much longer til one does!

[Recurve]

That gives me chills. There hasn't been a Cat 5 in the Keys since 1935, or a Cat 4 since Betsy 65 or Donna 60, AFAIK. There hasn't even been a direct hit by a 3 in 20 years that I can think of. It's been over 70 years since a Cat 5 and probably 40 since a cat 4, which have periods of 37 and 18 years.

[Anonymous]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

Yes, it is! Coastal Georgia hasn't been hit in a century, at least. I'm sure that there is some complacency all along the Hilton Head-Savanah-Jacksonville corridor.

[all_we_know_is_FALLING]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

Yes, it is! Coastal Georgia hasn't been hit in a century, at least. I'm sure that there is some complacency all along the Hilton Head-Savanah-Jacksonville corridor.

I hope I didn't jinx them. [uhoh]

[mempho]

Hey mempho, thanks for finding these links/maps! I find it interesting that a Cat 5 passing within 75 miles of NYC is a once in a 370 year event. If the average was to hold true, we don't have that much longer til one does!

Just remember, nature doesn't recognize a place as being "due." New York may go a millienium without their storm and then get 3 times in the next century. Look at the return periods on the western Florida panhandle, which had lived a charmed life for many years prior to Opal, as an example. They were way "overdue" for many years and then they got hit multiple times since Opal. Just a statistical average is all this is. Don't be the sucker who goes to the roulette wheel and says, "00 hasn't hit all night, so it's due." The wheel has no memory and mother nature doesn't work that way either. Long-term patterns come into play with these things so there will be times when Miami goes 30 years without a hit only to get hit twice in one year and twice in the next. Just the way it goes for the unlucky people that live there when it happens.

[Extremeweatherguy]

Houston/Galveston is just about due for another Cat. 3 storm (last one was Aug. 1983). We are also way overdue for Cat. 4+ storms. scary..

[Deputy Van Halen]

Just remember, nature doesn't recognize a place as being "due." New York may go a millienium without their storm and then get 3 times in the next century. Look at the return periods on the western Florida panhandle, which had lived a charmed life for many years prior to Opal, as an example. They were way "overdue" for many years and then they got hit multiple times since Opal. Just a statistical average is all this is. Don't be the sucker who goes to the roulette wheel and says, "00 hasn't hit all night, so it's due." The wheel has no memory and mother nature doesn't work that way either. Long-term patterns come into play with these things so there will be times when Miami goes 30 years without a hit only to get hit twice in one year and twice in the next. Just the way it goes for the unlucky people that live there when it happens.

I wonder if there are any REALLY LONG-term patterns that we don't even know about. We've all heard about the 20-30 year cycles in the Atlantic basin...which saw an upswing in the 1930's-1960's and then a lull and now another upswing. But what if there are cycles that span centuries? Maybe a thousand years ago, New York and Savannah were getting hit regularly while the Florida panhandle and North Carolina never had storms.

I read somewhere that the Bay of Bengal rarely gets cyclones now, when they used to get creamed on a regular basis, so that's what got me thinking about this.

[Anonymous]

Just remember, nature doesn't recognize a place as being "due." New York may go a millienium without their storm and then get 3 times in the next century. Look at the return periods on the western Florida panhandle, which had lived a charmed life for many years prior to Opal, as an example. They were way "overdue" for many years and then they got hit multiple times since Opal. Just a statistical average is all this is. Don't be the sucker who goes to the roulette wheel and says, "00 hasn't hit all night, so it's due." The wheel has no memory and mother nature doesn't work that way either. Long-term patterns come into play with these things so there will be times when Miami goes 30 years without a hit only to get hit twice in one year and twice in the next. Just the way it goes for the unlucky people that live there when it happens.

Very true! We really do not have any knowledge past 400-500 years ago, and, unfortunately, it seems like we never will. We could be in a much larger cycle than the 20-30 year one that we are in now.

I wonder if there are any REALLY LONG-term patterns that we don't even know about. We've all heard about the 20-30 year cycles in the Atlantic basin...which saw an upswing in the 1930's-1960's and then a lull and now another upswing. But what if there are cycles that span centuries? Maybe a thousand years ago, New York and Savannah were getting hit regularly while the Florida panhandle and North Carolina never had storms.

I read somewhere that the Bay of Bengal rarely gets cyclones now, when they used to get creamed on a regular basis, so that's what got me thinking about this.

[mempho]

Just remember, nature doesn't recognize a place as being "due." New York may go a millienium without their storm and then get 3 times in the next century. Look at the return periods on the western Florida panhandle, which had lived a charmed life for many years prior to Opal, as an example. They were way "overdue" for many years and then they got hit multiple times since Opal. Just a statistical average is all this is. Don't be the sucker who goes to the roulette wheel and says, "00 hasn't hit all night, so it's due." The wheel has no memory and mother nature doesn't work that way either. Long-term patterns come into play with these things so there will be times when Miami goes 30 years without a hit only to get hit twice in one year and twice in the next. Just the way it goes for the unlucky people that live there when it happens.

I wonder if there are any REALLY LONG-term patterns that we don't even know about. We've all heard about the 20-30 year cycles in the Atlantic basin...which saw an upswing in the 1930's-1960's and then a lull and now another upswing. But what if there are cycles that span centuries? Maybe a thousand years ago, New York and Savannah were getting hit regularly while the Florida panhandle and North Carolina never had storms.

I read somewhere that the Bay of Bengal rarely gets cyclones now, when they used to get creamed on a regular basis, so that's what got me thinking about this.

This is a very good point. I think we have a "decent" knowledge of the past few centuries because soil samples have been studied and so forth. We may, however, have some huge long-term swings with the patterns that we don't even know about. Like...how does the a slowing of the Gulf Stream preceding an ice age affect Atlantic activity? Interesting stuff.

[Anonymous]

Just remember, nature doesn't recognize a place as being "due." New York may go a millienium without their storm and then get 3 times in the next century. Look at the return periods on the western Florida panhandle, which had lived a charmed life for many years prior to Opal, as an example. They were way "overdue" for many years and then they got hit multiple times since Opal. Just a statistical average is all this is. Don't be the sucker who goes to the roulette wheel and says, "00 hasn't hit all night, so it's due." The wheel has no memory and mother nature doesn't work that way either. Long-term patterns come into play with these things so there will be times when Miami goes 30 years without a hit only to get hit twice in one year and twice in the next. Just the way it goes for the unlucky people that live there when it happens.

Oh, no, I know that nature doesn't recognize what areas are due...the FL panhandle example is perfect. That's why I said "if the average holds true"

[skufful]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

Yes, it is! Coastal Georgia hasn't been hit in a century, at least. I'm sure that there is some complacency all along the Hilton Head-Savanah-Jacksonville corridor.

Remember, David I believe was a Cat 5 at one time, althought only a Cat 1 when it hit Savannah in the 70's, so not a century unless you're talking only about CAT 5's

[Anonymous]

Remember, David I believe was a Cat 5 at one time, althought only a Cat 1 when it hit Savannah in the 70's, so not a century unless you're talking only about CAT 5's

Hey, thanks for bringing up David. I was suprised to read that David affected the entire EC, even affecting NYC. I was only talking about major hurricanes at landfall, though.

[weatherwindow]

That gives me chills. There hasn't been a Cat 5 in the Keys since 1935, or a Cat 4 since Betsy 65 or Donna 60, AFAIK. There hasn't even been a direct hit by a 3 in 20 years that I can think of. It's been over 70 years since a Cat 5 and probably 40 since a cat 4, which have periods of 37 and 18 years.

.....agreed, we certainly standout both literally and arithmetically...looking at the raw averages, we should be moving ...but we have such a skewed distribution, particularly kw and the lower keys. looking a little farther back into the 19th century may yield some sort of order....kw(and i will assume the lower keys) experienced a series of "major" hits(some subjective classification here) just prior to the beginning of the modern period(1851)...1831, 1835, 1842, 1844, and 1846...then a relatively quiet period until roughly the turn of the 20th century...then a series of major hits...1906, 1909, 1910, 1919...then the current lull...it looks as if a realistic major return period for kw might be in the vicinity of 70-80 years and it certainly appears that they come in "bunches"......rich

[baygirl_1]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

Yes, it is! Coastal Georgia hasn't been hit in a century, at least. I'm sure that there is some complacency all along the Hilton Head-Savanah-Jacksonville corridor.

I'm not sure about the attitudes of the folks living in the Savannah area, but I can tell you the officials seem somewhat prepared. My nephew goes to college there. When I visited, I noted that they have crossover lanes with large gates on the interstate that are there specifically for when a coastal evacuation is ordered. As it was explained to me, during an evacuation the gates would be opened allowing traffic to flow on all lanes of the interstate headed inland toward Macon. Also, my nephew's college has emergency plans ready to go that would transport all students to a school inland. Hopefully they won't have to use either plan--- esp. while he's there!

[Stratusxpeye]

Wow this is interesting. Where I'm at here in Tampa is the lowest number on all categories other than south-east florida. Interesting. We have nto had anything here in 80 years I belive 1921 was the last of anything over a cat 1 hitting us from the south-east riding through the middle of the state. But interesting data. Places I would have though would have a low return rate are twice or three times as high as where I am which I though would have had a really low return rate.

[caneman]

Wow this is interesting. Where I'm at here in Tampa is the lowest number on all categories other than south-east florida. Interesting. We have nto had anything here in 80 years I belive 1921 was the last of anything over a cat 1 hitting us from the south-east riding through the middle of the state. But interesting data. Places I would have though would have a low return rate are twice or three times as high as where I am which I though would have had a really low return rate.

It is a common mis-perception. People think just because we haven't take n a direct hit sonce 1921 that we haven't been impacted. Simply not true. Check out this link. This area gets affected ALOT! but just because we haven't taken a direct hit right up the Bay people act we're in some kind of safe zone.

http://www.hurricanecity.com/city/tampa.htm

[mempho]

Wow this is interesting. Where I'm at here in Tampa is the lowest number on all categories other than south-east florida. Interesting. We have nto had anything here in 80 years I belive 1921 was the last of anything over a cat 1 hitting us from the south-east riding through the middle of the state. But interesting data. Places I would have though would have a low return rate are twice or three times as high as where I am which I though would have had a really low return rate.

It is a common mis-perception. People think just because we haven't take n a direct hit sonce 1921 that we haven't been impacted. Simply not true. Check out this link. This area gets affected ALOT! but just because we haven't taken a direct hit right up the Bay people act we're in some kind of safe zone.

http://www.hurricanecity.com/city/tampa.htm

I really like the hurricane city database and I think that everyone should read it. I especially like the list of most affected places. Jim has something for everyone.

[mempho]

Very cool.

Savannah, GA appears to be one of the safer places to live if you want the best chance of not getting hit.

Savannah is in one of those places that it there is a narrower swath of "tracks" that will get a storm in there. Jacksonville, to a lesser extent, is the same way. For me, Tampa was the most surprising result. I wasn't exactly stunned that S. Florida was the worst place to be or that N. Carolina gets hit a lot and the Gulf numbers looked very reasonable to me. I was shocked, however, that Tampa has a risk as high as it does. Like others have said, Tampa hasn't been hit in years and it is protected from the normal east-west movement of hurricanes (especially Cape Verdes). However, I think the past two years have served as warning shots that majors do come into Florida's west coast and Pinnellas County sticks out of that west coast like a sore thumb just begging to catch storms coming from the south and southwest. It goes without saying that any storm making landfall in Pinnellas is going to throw surge from Tampa Bay into Hillsborough County.