Archive for the ‘Storm surge’ Tag
Enlarge images in this posting with left clicks.
ILLUSTRATION B – map of Citrus County showing locations of the Gulf Coastal Lowlands which are subject to storm surges, the sandy Brooksville Ridge occupying more than one-third of the area, and the Tsala Apopka Plain containing the majority of the county’s fresh water lakes –
– TWO INDEPENDENT LEFT CLICKS ENLARGE THE IMAGE ABOVE TO THE FULLEST –
I Am Very Happy Living In Citrus County.
Of course, being retired, being a nature-lover and being relatively healthy helps. All locations have pros and cons but with respect to the latter I have yet to regret the move with my extended family 9 years ago. We had experienced hurricanes and tropical storms through the years. Our house was a total loss in 1992’s category 5 hurricane Andrew; it was at ground zero in Homestead which is located 27.6 miles (as the crow flies) southwest of Miami. The house belonging to my wife’s folks, less than a mile away, had extensive damage. What a terrible mess was caused by the only hurricane to make landfall upon the U.S.A. that season. But when we moved to Citrus County 13 years later we were conscious of the fact that by leaving South Florida we had NOT left “hurricane country.” I felt that Citrus County would be safer in that respect but certainly not a hurricane-proof location. It didn’t take long for me to meet people who felt that there was something special about Citrus and other nearby counties that made a serious hurricane event almost inconceivable.
Complacency is a real problem in hurricane country. I don’t claim to be an expert on complacency but there have been times in my life where I might have contracted the disorder I call “terminal uniqueness.” Therefore, I am acquainted with denial, ignorance, procrastination, irresponsibility, and “living in a dream world” because I’ve been there; for all I know, I’m there still. I believe that every time I point a finger at someone, three are pointing back at me and this is written in that spirit. Thus, I’m not trying to indict anyone here; I’m just trying to state what appears to me to be true.
As I see it – Citrus County, as a whole, though probably not the “geographical poster child” for complacency when it comes to hurricanes and tropical storms, seems to be after the title – in spite of its experience with “The Florida Four in 2004” (see illustration C below). I’m not speaking of those who vigorously engage in emergency planning and increasing awareness in the community. And of course I’m not speaking to residents reading this who have engaged in effective advanced planning and preparation. No, I’m speaking of the average Jack and/or Jill occupying a dwelling in Citrus County; I acknowledge that there are plenty of exceptions. To be sure – this is not a problem exclusive to Citrus County. I believe it’s prevalent in all or nearly all parts of the country susceptible to tropical cyclonic weather. Please click on this graphic below for enlargement.
The four 2004 storm tracks above are dated for your convenience. For example: Tropical storm Bonnie’s track runs from August 3rd to August 14.
NOTE: For an infrared satellite loop of the majority of the 2004 season, click on the first link below. Date and time indicators appear along the bottom margin. Then for an animated loop which is easier to interpret click on the second link.
I moved to Florida in 1956 during my high school junior year and I don’t remember a time since when I have not been conscious of the potential for tropical weather to wreak havoc upon lives and property and I have always tried to be prepared. If you were to have simply driven by my house you could have observed elements of hurricane preparedness. That is still true today. It is a high priority item in my family. I have been an active advocate of hurricane awareness and preparation for many years. If anything, I hope that illustrations in this weblog posting will increase awareness at least among the few who see it. So let me call your attention to the illustration below. Most residents who see such illustrations are, at the very least, surprised. Naturally some point out that this covers a long period of time. But really, is 161 years a long time in the whole scheme of things? My point in showing this is: TROPICAL CYCLONES ARE A REALITY IN CITRUS COUNTY. Also, please be aware of the fact that the plot lines show the paths of the centers of storms and that the storms have a width that is not apparent here. The center of a storm does not have to come within just a few miles for it to be of great concern; the center can be many miles away.
Even before leaving Homestead for good in 2005 – while visiting Citrus County I detected the existence of a notion of immunity to any sort of serious tropical cyclonic weather (e.g. hurricanes, tropical storms). Though I have no scientific evidence to back this – I classify the “no-need-to-be-concerned” feeling as widespread among the Citrus County population. In fact, sometimes “low-to-no” hurricane probability has been drastically overstated here (I’ve heard it and I’ve heard about it). It seems that “The Florida Four in 2004 ” did very little to squelch the delusion. Still – I would have expected that particular season to have provided a huge “wake up call.”
NOTE: The “official” Florida Four in 2004 includes hurricane Charley which struck Punta Gorda on August 13 and later moved through South Carolina. It does not include tropical storm Bonnie.
Just a few weeks ago I overheard a hostess at a popular restaurant in adjacent Marion County telling a booth full of patrons, “We just don’t get hurricanes here.” Recently a friend of mine suggested that there was something about our county’s geography, specifically the Brooksville Ridge, that prevented hurricane visits. That reminded me of Muncie, Indiana where I used to live; it is alleged to be immune from tornadoes because of a particular bend in the river flowing through it. Also, a protective blessing from an Indian chief has been cited.
“The Florida Four in 2004” did not produce the extent of damage or flooding that raised eyebrows all over the nation and, for now, a sense of security from lethal storms seems to cling on. This is not a prediction nor is it my wish, but I do fear that a hurricane coming through this area has the potential to surprise a lot of people and make them wonder what they were thinking. And such an event could be deadly and most certainly destructive.
Storm Surge Potential
When I was looking for property in Citrus County one of my big concerns was the encroachment of wind-driven sea water with a storm – the so-called storm surge. Upon investigation I found what I expected – that if it was important to me personally to avoid surge potential I should avoid about one-third of the county’s land area – the western third.
NOTE: Illustration B, “map of Citrus County” might be useful to you here.
Most of that western third is undeveloped but there are two noteworthy communities within it, Homosassa and most of Crystal River. Therefore, early on I decided not to settle on the Gulf Coastal Lowlands but instead chose the Brooksville Ridge. In my opinion, the broad, hilly, sandy ridge is, by far, the safest place for a home or business in the county because of it’s higher elevations and greater ability to handle large amounts of precipitation often associated with a storm. The highest point in the county is within the Citrus Hills Golf Course above a 230′ contour – my Google Earth measurement has it at 235 feet.
ILLUSTRATION E – Storm surge portion of Citrus County, the western third (color-coded). T = tropical storm and the numbers represent hurricane categories. Left click to enlarge or go to the next illustration for more detail.
FOR STORM SURGE ZOOM CAPABILITIES, click on this link:
To be fair, Citrus county seems not to have been visited by category 5 or 4 hurricanes though at nearby Cedar Key a 1896 hurricane was a category 4 according to some estimates – crediting it with 135 mph winds.
NOTE: As far as we know, only three Category 5 storms have struck the U.S.A. – the 1935 Florida Keys or Labor Day hurricane, Hurricane Camille which hit Mississippi in 1969, and 1992’s Hurricane Andrew. The records aren’t good enough to say whether any earlier storms were Category 5 by today’s standards and they don’t go back very far with respect to the length of time that such storms have visited the North American mainland.
But lesser tropical cyclones, like tropical storms and tropical depressions, can produce both microbursts and tornadoes and simple straight-line gusts can far exceed the sustained wind velocity of such storms. Of course this is true for hurricanes too. Illustration G below shows initiation points of tornadoes spawned by tropical cyclones (e.g. tropical depressions, tropical storms, hurricanes) from 1995 through 2010. The entire report is available in the PDF format here:
– ILLUSTRATION G –
Please enlarge this with a left click. This illustration is on page 7 of Roger Edwards’ report which is available to you as the previous PDF document link titled Tornadoes Tropical Cyclones.
Recently, I looked into the proximity of past storms near my church and created a graphic for those who might be interested. Since the church is located in Lecanto and near the geographical center of Citrus County, I’m including the graphic in this weblog entry. Notice that I picked a small radius of 25 miles yet the illustration clearly shows a lot of activity. Had I picked a larger radius, say 50 miles, the graphic would show many more storms ( for an example of what I mean, see illustration D with a 100 mile radius centered on Inverness).
– ILLUSTRATION H –
Note: If you would like to utilize the program I used to derive illustration D and illustration H, here is a link:
The Relationship Between Wind Velocity and Its Potential Force
There is one last point I’d like to make and I have found in my years of teaching that there are many people who do not know this: One would think that the potential force of an 80 mph wind would be twice that of a 40 mph wind. But that is not true. The relationship is not linear – it is exponential. An 80 mph wind has FOUR TIMES the potential force of a 40 mph wind. When someone looking at the historical chart above sees mostly tropical storms (green) and category 1 hurricanes (yellow) they typically tend to minimize the dangers. They don’t realize that an 80 mph category 1 hurricane wind is far worse than a 60 mph tropical storm wind. I’ve done the math and, as it turns out, an 80 mph hurricane wind has 1.78 times the potential force of a 60 mph tropical storm wind (or close to twice the potential force). So, in even more simple terms, small increases in wind velocity result in large increases in potential force! For more discussion on the relationship between velocity and force, click on this link to a previous weblog entry:
My next mission is to discuss this with some people in the area to learn their attitudes and feelings on the subject. I’m sure I will learn a lot and gain more knowledge and insight. For example, I’ll bet there are some who just don’t feel it’s worth the effort – that they will just evacuate and let insurance take care of things, or maybe take some losses and leave for good if a serious storm messes things up. Others must find permanent window and door protection to be “cost prohibitive” and have plans to somehow temporarily protect those openings – maybe at the last minute. None of those approaches work for me; there are just too many variables. For example, try buying plywood when it becomes fairly clear that a hurricane is coming your way. Or – consider what it might be like if you do plan to evacuate but wait too long and are unable to do so. Being inside a home that is breaking apart during a serious hurricane is no picnic.
NOTE: See link below to “Window Protection Is Essential”.
I suspect that there are many who feel they have thought things through and that their apparent inaction is merely a function of our individual differences in thinking. Perhaps they do indeed have a “plan” albeit different than mine. What’s the saying – “Different strokes for different folks”? Regardless, I strongly recommend advanced preparation.
I observed complacency among many people in pre-Andrew Homestead and suspect it exists there again because, after all, that was 22 years ago. So why should I expect a greater awareness and more obvious preparation along the Nature Coast where Citrus County is located? The fact is, I don’t. But I can dream, can’t I?
Citrus County Emergency Management – http://www.sheriffcitrus.org/EM/
Disaster Preparedness (Florida Department of Health – Citrus County) http://www.floridahealth.gov/chdCitrus/disasterpreparedness.htm
Hurricane misconceptions: https://cloudman23.wordpress.com/2008/09/23/952/
Saffir-Simpson hurricane categories: http://www.nhc.noaa.gov/aboutsshws.php
Sustained winds: http://www.aoml.noaa.gov/hrd/tcfaq/D4.html
Window protection is essential: https://cloudman23.wordpress.com/2008/09/08/window-protection-for-hurricanes-is-essential/
The effects of hurricane winds upon a house: https://cloudman23.wordpress.com/2008/09/10/the-effect-of-hurricane-winds-upon-a-house/
Hurricane focus on Central Florida: https://cloudman23.wordpress.com/2008/09/13/hurricane-focus-on-central-florida/
Why is Florida so humid? https://cloudman23.wordpress.com/2009/07/04/why-is-florida-so-humid/
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Paloma is now a “high-end” category 1 hurricane and continues to strengthen. The greatest concerns throughout the Caymans are high winds – storm surge concerns are not as pressing. Jamaica is expected to get only fringe winds. Paloma is expected to continue toward the northeast, travel across Cuba and into the Bahamas.
Those of you who have studied the circulation of air with tropical cyclonic systems can probably “see” in the satellite image above both inflow and outflow cloud patterns. For those who are not familiar with the difference between the two I am including an image below of hurricane Ike on September 9, 2008. He is centered just offshore of northwest Cuba. I have drawn air flow arrows to show the cyclonic inflow (red) and the flow that occurs aloft, anticyclonic outflow (blue).
Inflow consists of the harder-edged clouds with sharp contrast – Outflow consists of the more diffuse cirrus and cirrostratus of the upper layer.
I posted an item on Sept. 21, 2008 about the elevated structure with cement block exterior walls at the upper level (pictured at the very end of this entry). That original post is still contained in this web-log. In this post that you are now reading, I am adding additional comments in “blue” to get you (and me) up to date. This has gone back and forth and I hope the identity of the building and the stated design of the block walls is correct. It worries me because anyone in there could have been seriously injured or worse from collapsing cement blocks. This first photograph is of a cement block structure In the Naranja Lakes Condominium Development near Homestead, Florida. In this particular structure there was a fatality due to poured concrete headers and blocks coming down upon a resident huddled inside – a real tragedy. There were at least 3 such fatalities in that neighborhood; it’s amazing that there were not more. TWO INDEPENDENT LEFT CLICKS SHOULD ENLARGE THIS IMAGE A GREAT DEAL.
This next paragraph reflects that I had already made a previous change in the original entry.
It is my understanding that the structure (pictured below) belongs to a yacht club. A reader wrote in after I originally posted this because I had misidentified it as the Houston Yacht Club. However, he indicated that the Houston Yacht Club is “a three story coral colored structure and while some water entered the first floor it is essentially undamaged.” You can check out his comment.
Since then, a couple of readers have identified the building as belonging to the Seabrook Sailing Club just north of the Clear Creek channel. “Kent” adds, “The cinder-block wash-away walls collapsed as designed, leaving the shell structure intact. It was originally built after Hurricane Carla in the early 1960s. Hurricane Alicia did a similar number on the building in 1983. I think the club is trying to decide if they should rebuild on the current shell or scrap it.” End quote.
Though this building is elevated and held fast on its foundation, the surge was too high and the waves too forceful for the cement block. I don’t believe this damage can be attributed directly to wind force but rather, the surge with its waves on top. For those of you who have felt the pounding of moderate surf against your body – imagine what this cement block must have endured before yielding. I see wires and perhaps some straps but I see no evidence of corefill in the block nor do I see very much rebar reinforcement in the image. At the time that I wrote this I had no idea that upper level walls were deliberately built to wash away. If this is true, so much for the contents and/or anyone who might have been unable to get out because they waited too long. On the other hand, maybe it was just used for storage. I had heard of “break-away” lower level walls. In fact I have a friend who built a pole house with that design. For quick information rebar and poured concrete reinforcement read the second paragraph in the following link and click on the photo on the bottom right.
Please visit the rest of this web-log go to “blog” at the top of this page or click here. https://cloudman23.wordpress.com/. If you are interested in weather, there are some tutorials scattered about and more will be added in time.
It is my understanding that this structure (below) belongs to a yacht club. A reader wrote in after I originally posted this because I had misidentified it as the Houston Yacht Club. However, he indicated that the Houston Yacht Club is “a three story coral colored structure and while some water entered the first floor it is essentially undamaged.” You can check out his comment.
Though this building is elevated and held fast on its foundation, the surge was too high and the waves too forceful for the cement block. I don’t believe this damage can be attributed directly to wind force but rather, the surge with its waves on top. For those of you who have felt the pounding of moderate surf against your body – imagine what this cement block must have endured before yielding. I see wires and perhaps some straps but I see no evidence of corefill in the block nor do I see very much rebar reinforcement in the image. For quick information on that type of reinforcement read the second paragraph in the following link and click on the photo on the bottom right.
A footnote for my regular readers: You can check for yourself but it looks according to the models as though the tropical disturbance addressed in the previous post is going to move northward. Still, I fear for those in Hispaniola and Puerto Rico. The rains are something they don’t need right now.
Please visit the rest of this web-log at https://cloudman23.wordpress.com/. If you are interested in weather, there are some tutorials scattered about and more will be added in time.
HERE ARE LINKS TO TWO REPORT ON
MOODY GARDENS AFTER IKE:
What follows is the complete 8:19 PM Central Daylight Time statement from the Galveston Office of the National Hurricane Center. This was for immediate broadcast. It is very long. I am posting the entire statement for the benefit of those who know details of the following areas from having lived there or having family and/or friends there. This addresses the following counties: BRAZORIA-CHAMBERS-GALVESTON-HARRIS-JACKSON-LIBERTY-MATAGORDA. Continue reading
Above I have posted an image showing all of the hurricanes and tropical storms that have come within 50 statute miles of Houston, Texas from 1928 through 2007. Many verified events occurred before 1928, including the most infamous 1900 Galveston hurricane. LEFT CLICKING ON THE IMAGE WILL ENLARGE IT. I prepared this chart using a program with a menu whereby I could select the city and pick the time frame. For your information, Galveston is 45.2 statute miles from the center of Houston (as the crow flies).
It illustrates that those cities are indeed in hurricane territory and that no one should be surprised that a storm such as Ike is now threatening them (and others). Just as it is where I live in Florida, it goes with the territory. People who live in that coastal area should not be reading this now unless they have gotten out of there. If you are currently somewhere else along the Texas and West Louisiana coast, please be prepared to seek higher ground inland. My opinion is that the sooner you make a move, the better. Why risk it? Of course there are hazards involved in evacuating too and you must be sober, wide awake, and thus alert.
Though I expect this to be renewed/revised soon, here is an EXCERPT from the most recent official statement by the Galveston office of the National Hurricane Center:
Statement as of 4:19 PM CDT on September 11, 2008
… Storm surge and storm tide…
Tide levels will begin rising Friday morning and will exceed
5 feet above mean lower low water along the Upper Texas coast and
along the shorelines of the bays by mid to late morning Friday.
Water levels will rise rapidly beginning late afternoon Friday as
the storm surge moves in with water levels peaking Friday night
and early Saturday. Maximum storm tide levels are highly dependent
on the track of the storm and variations in the track of only 15
miles can make differences of several feet more or less from some
of these values.
Maximum water levels forecast:
Gulf-facing coastline west of Sargent… 5 to 8 feet
Shoreline of Matagorda Bay… 5 to 8 feet
Gulf-facing coastline Sargent to High Island
including Galveston Island… … 12 to 16 feet
Shoreline of Galveston Bay… 15 to 22 feet
Life threatening inundation likely!
All neighborhoods… and possibly entire coastal communities…
will be inundated during the period of peak storm tide. Persons
not heeding evacuation orders in single family one or two story
homes will face certain death. Many residences of average
construction directly on the coast will be destroyed. Widespread
and devastating personal property damage is likely elsewhere.
Vehicles left behind will likely be swept away. Numerous roads
will be swamped… some may be washed away by the water. Entire
flood prone coastal communities will be cutoff. Water levels may
exceed 9 feet for more than a mile inland. Coastal residents in
multi-story facilities risk being cutoff. Conditions will be
worsened by battering waves. Such waves will exacerbate property
damage… with massive destruction of homes… including those of
block construction. Damage from beach erosion could take years to