200 MPH Hurricane

[patsmsg]

Here's a question that might be more appropriate to a separate thread, but can somebody tell me if there is a factor of intensity/damage increase relating to hurricanes.

Let me try that again, a 4 on the Richter scale is 10 times more damaging than an earthquake measuring 3. So my question is, is a cat 3 10 times more damaging than a cat 2, or maybe a 150 mph 10 times more powerful than a 130 mph hurricane, or can any such reference be made?

It would be interesting to me to know what it really means, in practical terms when a storm grows from a 100 mph to 130 or whatever.

[DoctorHurricane2003]

There is a really good graphic that the weather channel uses when hurricanes are making landfall regarding wind damage and it shows the exponential curve of damage vs. wind speed in all categories...not sure if they have it 24/7 on their site...but you can go look.

[Mississippi Storm Magnet]

Here's a question that might be more appropriate to a separate thread, but can somebody tell me if there is a factor of intensity/damage increase relating to hurricanes.

Let me try that again, a 4 on the Richter scale is 10 times more damaging than an earthquake measuring 3. So my question is, is a cat 3 10 times more damaging than a cat 2, or maybe a 150 mph 10 times more powerful than a 130 mph hurricane, or can any such reference be made?

It would be interesting to me to know what it really means, in practical terms when a storm grows from a 100 mph to 130 or whatever.

It is exponential, but I am not sure how much. I would think it would be e raised to some power. (2.71828^x)

Maybe Saffir-Simpson used this. Maybe the "categorys" are the exponents. And the results are the "damage".

Category 1 = e^1 = 2.718
Category 2 = e^2 = 7.389
Category 3 = e^3 = 20.086
Category 4 = e^4 = 54.598
Category 5 = e^5 = 148.413

Heck, I don't know, but that sounds good. I am truly a nerd.

I'll research this some more, as I want to know the answer also.

[dhweather]

WARNING: A LOT OF TECHNICAL CRUD BELOW

A detailed thermodynamic analysis has been done by quite a few people. Holland (1997), Emmanuel (1995), and others.

A theory of Maxium Potential Intensity (MPI) based primarily on Sea Surface Temperatures and Thermodynamic Law was developed. A quite detailed analysis is here:

http://www3.sympatico.ca/louis.michaud/ ... RTICLE.pdf

A little more understandible explanation of MPI is here:

http://www.cira.colostate.edu/RAMM/KFIn ... ised_1.doc

The equation for MPI is:

MPI = A + B*e^C*(T-T0)

where MPI = knots
A = 38.21
B = 170.72
e = 2.71828
C = 0.1909
T = Sea Surface Temp in C
T0 = 30

So 30 degree SST = MPI of 244.8 knots = 282 mph

A LOT of other factors come into play. That is why MPI is usually a LOT higher than what is actually observed.


Thanks for reading if you got this far!

Man, you are a geek.

[dhweather]

I should add, it's quite likely that Camille had 200MPH sustained winds.
We'll never know for sure, she destroyed all of the anemometers remotely near her core. Most were broken at 190MPH sustained.

[patsmsg]

I should add, it's quite likely that Camille had 200MPH sustained winds.
We'll never know for sure, she destroyed all of the anemometers remotely near her core. Most were broken at 190MPH sustained.

Yes, I know. Being from the MS coast, I've heard all of that. (and believe it myself)... But that was never official. Also, I've seen some out here claim 185 never actually happened, but was an error.

[HurryKane]

Here's a question that might be more appropriate to a separate thread, but can somebody tell me if there is a factor of intensity/damage increase relating to hurricanes.

Let me try that again, a 4 on the Richter scale is 10 times more damaging than an earthquake measuring 3. So my question is, is a cat 3 10 times more damaging than a cat 2, or maybe a 150 mph 10 times more powerful than a 130 mph hurricane, or can any such reference be made?

It would be interesting to me to know what it really means, in practical terms when a storm grows from a 100 mph to 130 or whatever.

It's like this: dynamic pressure increases or decreases as the square of the increasing or decreasing velocity of ze wind:

Pressure = 1/2 * density * velocity^^2

Let's say we keep density (and the 1/2 ha ha) constant, and call it C = 1/2 * density

Case A: 100 mph: Pressure = C*100^^2 = 10000*C
Case B: 120 mph: Pressure = C*120^^2 = 14400*C (wind speed = 1.2 times that of A, while pressure = 1.44*A)
Case C: 140 mph: Pressure = C*140^^2 = 19600*C (wind speed = 1.4 times that of A, while pressure = 1.96*A)
Case D: 160 mph: Pressure = C*160^^2 = 25600*C (wind speed = 1.6 times that of A, while pressure = 2.56*A)

In other words, a 20% increase in wind speed equals a 44% increase in the force the wind applied to a wall; a 40% increase in wind speed equals a 96% increase in the force of the wind, and a 60% increase in wind speed equals a 156% increase in the force of the wind.

I suck at English units so I left them out. If you need more, come by the office for some fluid dynamics and Nerf basketball.

(edited for a small typo)

[dhweather]

Nice read on Camille:


http://www.geocities.com/hurricanene/hu ... amille.htm

[Mississippi Storm Magnet]

Yes, I am a geek.......

The force of the wind will vary with the square of the windspeed.

The kinetic energy is E= 1/2 * m * v^2

So if you double the velocity, you get 4X the kinetic energy.

A 40 mph Tropical storm would do "x" damage. Very little.

An 80 mph hurricane would do "4x" damage of the tropical storm.

A 160 mph hurricane would do "16x" damage of the tropical storm, and "4x" damage of the 80 mph hurricane.

[HurryKane]

Yes, I am a geek.......

The force of the wind will vary with the square of the windspeed.

The kinetic energy is E= 1/2 * m * v^2

So if you double the velocity, you get 4X the kinetic energy.

A 40 mph Tropical storm would do "x" damage. Very little.

An 80 mph hurricane would do "4x" damage of the tropical storm.

A 160 mph hurricane would do "16x" damage of the tropical storm, and "4x" damage of the 80 mph hurricane.

I beat you to it, babe. Look up a few posts

[dhweather]

And people wonder what HurryKane, Mississippi Storm Magnet, DHweather, and Mrs. DHweather talk about when we go out to eat?

[Normandy]

I dont think Camille had 200 mph winds, since most claim she was large (with a 909 pressure)...even if she was small she still doesnt have the pressure to have 200 mph winds imo. Also the north gulf does tend to weaken storms.... I tink she had winds of about 175 mph.

The only 200 mph storm I think was 1935 keys hurricane.

[HurryKane]

And people wonder what HurryKane, Mississippi Storm Magnet, DHweather, and Mrs. DHweather talk about when we go out to eat?

Everybody else, of course.

And nerd stuff too.

[patsmsg]

Normandy: You could be right, but the NHC estimates 190...so you probably aren't.

[Normandy]

Normandy: You could be right, but the NHC estimates 190...so you probably aren't.

Well...point is its their estimate...there isnt concrete evidence to prove it had 200 mph winds...so any estimate is an opinion.

Also, with 200 mph winds I wouldn't expect a tree standing....and lost of trees are still there in the damage pics.

[dhweather]

The ones standing are Live Oaks, which are legendary for their strength.

As HurryKane pointed out, Old Ironsides was made from Live Oaks.

[HurryKane]

The ones standing are Live Oaks, which are legendary for their strength.

As HurryKane pointed out, Old Ironsides was made from Live Oaks.

I think most of the times when (if?) Live Oaks fall it's due to saturated ground that can no longer hold on to the roots. They don't ever just break in half that I've seen.

[patsmsg]

Normandy: You could be right, but the NHC estimates 190...so you probably aren't.

Well...point is its their estimate...there isnt concrete evidence to prove it had 200 mph winds...so any estimate is an opinion.

Also, with 200 mph winds I wouldn't expect a tree standing....and lost of trees are still there in the damage pics.

Like I said, I'm willing to grant that you could be right. I just happen to think they are pretty good at what the do. I mean, no offense intended by my favoring the NHC's estimate.

It does puzzle me a bit why you are so much more confident in the measurements of the Keys hurricane which come from 1935. There were no Hurricane Hunters, etc... Were they better at measuring wind speed back then? Or is it that you have before and after photos showing no trees after the keys hurricane, or what? What I mean is, what makes you more willing to accept the data on the Keys hurricane?

[vbhoutex]

The ones standing are Live Oaks, which are legendary for their strength.

As HurryKane pointed out, Old Ironsides was made from Live Oaks.

You beat me too it dh.

Normandy, if you had seen the damage I saw and I am not talking surge damage, you would believe that Camille had 200 mph winds. What do you base your 175mph on?

[Normandy]

Normandy: You could be right, but the NHC estimates 190...so you probably aren't.

Well...point is its their estimate...there isnt concrete evidence to prove it had 200 mph winds...so any estimate is an opinion.

Also, with 200 mph winds I wouldn't expect a tree standing....and lost of trees are still there in the damage pics.

Like I said, I'm willing to grant that you could be right. I just happen to think they are pretty good at what the do. I mean, no offense intended by my favoring the NHC's estimate.

It does puzzle me a bit why you are so much more confident in the measurements of the Keys hurricane which come from 1935. There were no Hurricane Hunters, etc... Were they better at measuring wind speed back then? Or is it that you have before and after photos showing no trees after the keys hurricane, or what? What I mean is, what makes you more willing to accept the data on the Keys hurricane?

The Labor day hurricane was as small as Charley with a pressure 50+ millibars lower...and Charley was a borderline Cat5. You get the idea. I only think the Labor Day was 200 mph because of its extreme size and wind gradient.

Normandy, if you had seen the damage I saw and I am not talking surge damage, you would believe that Camille had 200 mph winds. What do you base your 175mph on?

I have heard people say that Camille was a large storm, and that people 50+ miles away from the center had 100 mph winds. That sounds Gilbert-esque. Gilbert had a pressure of 888....which is 21 mb lower than Camille, and had winds nowhere near 200 sustained. Even if Camille was a small as the Labor Day hurricane, she still wouldnt have been as intense as her pressure was far higher.

I think Camille was an easy Cat5, but one with 175 mph winds....slightly stronger than Andrew.