Were intensities of past hurricanes OVERESTIMATED????

[Tampa Bay Hurricane]

Many past hurricanes in hurricane archives show a large number
of major hurricanes hitting Florida during the 1940s and up to
Easy in 1950. Were the intensities overestimated? I've heard some
people say yes, some people say no, so I would like to know what's
really the case??

[WxGuy1]

I don't think many of us on this board can say with any sort of authority whether they were or not. I think after-action reports may be a little liberal with the wind speeds, similar to the way some old tornadoes are over-estimated. Heck, go back and watch some early TV shows on tornadoes (from the 50s-70s) and you'll hear the commentator talk about how winds in tornadoes may be as strong as 600mph. LOL Obviously, we know this isn't the case. The winds required to destroy a 1950s house are probably much less than the winds necessary to produce the same damage in a nearly-built house, largely thanks to new building codes and regulations.

[Ixolib]

...The winds required to destroy a 1950s house are probably much less than the winds necessary to produce the same damage in a newly-built house, largely thanks to new building codes and regulations.

Actually, I saw a LOT of "newly" built houses fly with the wind in Katrina. But my 1946 home did just fine (relatively speaking) as did many others of the same vintage. I'll take an older-built house over a newer one any day.

As a side note, I am in the process of some extreme remodeling as a result of Katrina's surge, and I can surely testify that the nails they used in this old house are considerably beefier than the ones I see in the newer ones. And that includes everything from the framing to the trim. And not only is the lumber much more dense or solid, it is also used in a greater quantity - i.e., no scrimping on the amount of lumber. Seems everything is "overdone", and thankfully so, I believe!!

One of the primary failures I've seen in the newer homes is the way they nail the rafters together at the gables, and then the way they nail the rafters to the top plate and/or ceiling joists. Not sure what they call 'me, but I call 'em "nail plates". They may make the building process much faster (and thereby cheaper in labor), but they surely don't stand up well to a cat 2/3 cane!!

Okay, sorry to stray so far off topic. Back on now...

[Hurricanehink]

One word: Ethel.....
That might not be enough. In 1960, Ethel "rapidly" strengthened to a Category 5 strength, and hours later weakened back to a tropical storm. It had a pressure of 981, so I doubt it was even a major hurricane.

[quandary]

The other curious this is, however, that we have had 3 of the strongest storms on record this year. That makes no sense statistically. The mean in terms of strongest storms per year is something like .3 with a low standard deviation. This makes 2005 have a likelihood of something like .001%. A more reasonable explanation would be that other years had stronger storms with pressures that were comparable to this year's storm. Which would suggest that the storms intensities were underestimated. Which goes against conventional wisdom.

[HurricaneBill]

Some were overestimated. Others were underestimated.

In 1958, Hurricane Cleo was listed as having sustained winds of 160 mph. Lowest pressure was 948 mb. I think Cleo was more likely a upper end Category 3 or low-end Category 4. Either that or the lowest pressure was missed.

Also in 1958, Hurricane Daisy was listed as having sustained winds of 125 mph. However, Daisy's lowest pressure was 935 mb. It's possible Daisy was a Category 4 instead of a 3.

As for Ethel in 1960, I don't think she higher than a Category 2 or possibly low end 3. However, Ethel did make landfall as a strong Category 1 with recorded sustained winds around 90 mph.

[HurricaneBill]

I think midget hurricanes were probably underestimated.

[WxGuy1]

The other curious this is, however, that we have had 3 of the strongest storms on record this year.

We've had 3 of the top 6-7 most intense hurricances in current records. Not sure if you meant this or not, as the first time I read your post it sounded like we had THE 3 most intense storm on record.

[aerojad]

One word: Ethel.....

Two words: loop current

[Anonymous]

One word: Ethel.....

Two words: loop current

We saw Wilma go from 75 mph to 175 mph in less than a day...Ethel deepening is possible. I think Ethel was more around 125-135 mph, then weakened in a Lili-type fasion before landfall.

[Hurricanehink]

One word: Ethel.....

Two words: loop current

We saw Wilma go from 75 mph to 175 mph in less than a day...Ethel deepening is possible. I think Ethel was more around 125-135 mph, then weakened in a Lili-type fasion before landfall.

I'm just saying that because the pressure was 981 with flight level winds of 160. It may have been a Cat. 3, but I just don't see how conditions could be ideal for 12 hours, then horrendous 6 hours later.

[mtm4319]

One word: Ethel.....

Two words: loop current

We saw Wilma go from 75 mph to 175 mph in less than a day...Ethel deepening is possible. I think Ethel was more around 125-135 mph, then weakened in a Lili-type fasion before landfall.

I'm just saying that because the pressure was 981 with flight level winds of 160. It may have been a Cat. 3, but I just don't see how conditions could be ideal for 12 hours, then horrendous 6 hours later.

The 981 pressure reading came when winds were estimated at 110 knots. That's still pretty high, although Charley last year was a category 2 (90 knots) with a pressure of 980 mb.

[weatherwindow]

i remember a comment made by chris landsea....in one of the reanalysis presentations that there was a systematic flaw in recon windspeed data prior to the late 60s...other examples of potential mistakes have been mentioned in this thread, another candidate may be inez 1966 with extrapolated pressure of 938mb and sustained winds of 175 mph in the eastern caribbean...maybe incorrect or just another outlier such as wilma, sub-920 and low to mid cat 4........good to be back in the light ....rich

[f5]

I think midget hurricanes were probably underestimated.

Charley can hear you

[Jim Cantore]

I think Camille may have been overestimated

Why?

Her name is spelled K-A-T-R-I-N-A

[Derek Ortt]

there seems to be a very large overestimate (by 10-20% until the late 1980's) as the flight level reduction was simply not made, then for the most part an under-estimate from about 1988 through 1997 due to applying a uniform 80% rule (when its 90% at 700mb), except for the 1500 ft flight level, where little reduction was used (Klaus likely will be stripped of cane status on the re-analysis due to this fact), then good since 1998

[Jim Cantore]

I agree ortt other then the fact that they've had to correct themselves twice in the last 2 years and maybe once or twice this year

[sp0n9e]

i've read somewhere on noaa's site that wind speeds were in fact on average 10mph higher in the 1960's and 1970's, but i'm looking for a source. other than that, you may notice cycles in the hurricane intensities and hurricane frequencies. i don't believe the 40's and 50's hurricanes have been thought of as wrongfully estimated before as far as noaa says.

aha, just found the source:

http://www.aoml.noaa.gov/hrd/hurdat/