Hurricane Ian

[Casuarina Head]

Also, the photos I've seen of wind damage from Hurricane Ian look pretty intense to me - not as intense as Andrew or Dorian, sure, but then again you have to remember those are extreme examples.

^ @TH2002 Please take a look at images of coconut palms on the beachfront in Fort Myers Beach. Note that palms on the immediate waterfront, on the right edge of the preceding image, show virtually no injury to their fronds. Those palms appear to be approximately 30’ tall, well above the surge that was documented at the same location. Storm chaser Max Olson’s camera was approximately 12’ above ground level, yet the palms that are covered by water in his footage appear to be ~6’ AGL, and the TCR mentions that this was partly due to waves rather than surge. So those 30’ palms would have escaped wave-and-surge-related damage to their fronds, indicating that the absence of visible damage was due to a lack of 130-kt wind rather than being covered by water. Fort Myers Beach, being sited in the southeastern eyewall, experienced the strongest winds and peak surge in Ian, which would have been in the southeastern quadrant of a northeastward-curving hurricane. Had MSW of 130 kt been present, the palms would have shredded, the surge would have been higher, and the video would not have survived to begin with. For example, take a look at coconut palms on the shoreline in Miami Beach following the passage of the northeastern quadrant of the 1926 Miami hurricane, which was 125 kt at LF. Those palms’ fronds were completely shredded, despite an absence of big surge on the Atlantic coast of South Florida.

 

[SouthFLwx]

^ @TH2002 Please take a look at images of coconut palms on the beachfront in Fort Myers Beach. Note that palms on the immediate waterfront, on the right edge of the preceding image, show virtually no injury to their fronds. Those palms appear to be approximately 30’ tall, well above the surge that was documented at the same location. Storm chaser Max Olson’s camera was approximately 12’ above ground level, yet the palms that are covered by water in his footage appear to be ~6’ AGL, and the TCR mentions that this was partly due to waves rather than surge. So those 30’ palms would have escaped wave-and-surge-related damage to their fronds, indicating that the absence of visible damage was due to a lack of 130-kt wind rather than being covered by water. Fort Myers Beach, being sited in the southeastern eyewall, experienced the strongest winds and peak surge in Ian, which would have been in the southeastern quadrant of a northeastward-curving hurricane. Had MSW of 130 kt been present, the palms would have shredded, the surge would have been higher, and the video would not have survived to begin with. For example, take a look at coconut palms on the shoreline in Miami Beach following the passage of the northeastern quadrant of the 1926 Miami hurricane, which was 125 kt at LF. Those palms’ fronds were completely shredded, despite an absence of big surge on the Atlantic coast of South Florida.

Do you realize how resilient coconut palms are?

 

[Casuarina Head]

Do you realize how resilient coconut palms are?

Yes, but why did 130-kt Ian barely do any damage to coconut palms on the beachfront vs. the 125-kt Miami hurricane of 1926? The palms were exposed to the strongest winds in both cases.

 

[SouthFLwx]

Yes, but why did 130-kt Ian barely do any damage to coconut palms on the beachfront vs. the 125-kt Miami hurricane of 1926? The palms were exposed to the strongest winds in both cases.

Hurricane Ian's strongest winds didn't hit Ft. Myers Beach. They were located in the western quadrant of the eyewall (which is where the deepest convection was), confined to a small area, and there is a very real chance that they didn't even make it onshore due to land friction.

 

[Casuarina Head]

Hurricane Ian's strongest winds didn't hit Ft. Myers Beach. They were located in the western quadrant of the eyewall (which is where the deepest convection was), confined to a small area, and there is a very real chance that they didn't even make it onshore due to land friction.

Given that Ian was moving north of due east during landfall, why would that possibly have been the case? Wouldn’t the strongest surface winds have occurred south and east of the eye, given forward trajectory? I know that radar and aircraft indicated that the strongest winds were in the western quadrant, but reconnaissance measured FL winds of 133 kt SSE of the eye at 1758Z, about an hour prior to LF, which would indicate 10-m winds of ~120 kt. I’d imagine that 120-kt winds would cause a lot more visible damage to those coconut palms than is shown. As mentioned above, the 1926 hurricane was 125 kt at LF and completely shredded beachfront coconut palms, so, if anything, even winds of less than 120 kt would have caused greater damage than is visible in the imagery, unless there is another explanation...

At 3:49 the following video does show stripped coconut palms. But these seem to have been subject to wind-tunnelling behind the condominium, for nearby coconut palms on the waterfront do not show the same degree of injury (4:55 shows this quite well):



Bottom line: I myself am surprised. The reconnaissance data would certainly support the NHC’s MSW of 130 kt at LF. My question is, Why doesn’t the damage seem to add up?

 

[SouthFLwx]

Given that Ian was moving north of due east during landfall, why would that possibly have been the case? Wouldn’t the strongest surface winds have occurred south and east of the eye, given forward trajectory? I know that radar and aircraft indicated that the strongest winds were in the western quadrant, but reconnaissance measured FL winds of 133 kt SSE of the eye at 1758Z, about an hour prior to LF, which would indicate 10-m winds of ~120 kt. I’d imagine that 120-kt winds would cause a lot more visible damage to those coconut palms than is shown. As mentioned above, the 1926 hurricane was 125 kt at LF and completely shredded beachfront coconut palms, so, if anything, even winds of less than 120 kt would have caused greater damage than is visible in the imagery, unless there is another explanation...

At 3:49 the following video does show stripped coconut palms. But these seem to have been subject to wind-tunnelling behind the condominium, for nearby coconut palms on the waterfront do not show the same degree of injury (4:55 shows this quite well):



Bottom line: I myself am surprised. The reconnaissance data would certainly support the NHC’s MSW of 130 kt at LF. My question is, Why doesn’t the damage seem to add up?

Sometimes it’s hard to distinguish surge damage from wind damage and the degree of damage that’s inflicted upon land from wind is affected by many factors.

 

[TH2002]

^ @TH2002 Please take a look at images of coconut palms on the beachfront in Fort Myers Beach. Note that palms on the immediate waterfront, on the right edge of the preceding image, show virtually no injury to their fronds. Those palms appear to be approximately 30’ tall, well above the surge that was documented at the same location. Storm chaser Max Olson’s camera was approximately 12’ above ground level, yet the palms that are covered by water in his footage appear to be ~6’ AGL, and the TCR mentions that this was partly due to waves rather than surge. So those 30’ palms would have escaped wave-and-surge-related damage to their fronds, indicating that the absence of visible damage was due to a lack of 130-kt wind rather than being covered by water. Fort Myers Beach, being sited in the southeastern eyewall, experienced the strongest winds and peak surge in Ian, which would have been in the southeastern quadrant of a northeastward-curving hurricane. Had MSW of 130 kt been present, the palms would have shredded, the surge would have been higher, and the video would not have survived to begin with. For example, take a look at coconut palms on the shoreline in Miami Beach following the passage of the northeastern quadrant of the 1926 Miami hurricane, which was 125 kt at LF. Those palms’ fronds were completely shredded, despite an absence of big surge on the Atlantic coast of South Florida.

There are simply too many variables to be considered with storm surge; the Saffir-Simpson scale ranks hurricanes by sustained wind speeds for a reason. Katrina’s peak surge was nearly twice as high as Ian’s despite it having slightly lower sustained winds at landfall and Andrew’s storm surge peaked at around 17 feet (again, lower than Katrina) despite being a solid category 5 at landfall. Also, I second what @SouthFLwx said about coconut palms and their resilience to hurricane winds as well as the location of Ian’s maximum winds.

 

[SouthFLwx]

There are simply too many variables to be considered with storm surge; the Saffir-Simpson scale ranks hurricanes by sustained wind speeds for a reason. Katrina’s peak surge was nearly twice as high as Ian’s despite it having slightly lower sustained winds at landfall and Andrew’s storm surge peaked at around 17 feet (again, lower than Katrina) despite being a solid category 5 at landfall. Also, I second what @SouthFLwx said about coconut palms and their resilience to hurricane winds as well as the location of Ian’s maximum winds.

Andrew had a 17 ft. storm surge at landfall? I thought it was lower than that.

 

[TH2002]

Andrew had a 17 ft. storm surge at landfall? I thought it was lower than that.

Peak surge was 16.9 feet between Homestead and Biscayne Bay.