Archive for the ‘Weather hazards’ Category
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/
Thanks to the National Weather Service Hydrometeorological Prediction Center for this graphic.
What you see is a 5 day forecast for the total rainfall in inches between 8 AM Eastern Daylight Time Sunday and 8 AM EDT on Friday . The feared 15″ of rain in the New Orleans area predicted 36 hours earlier seems highly unlikely. For ease in reading, left click the image two times independently for full enlargement.
Thanks to the National Weather Service Hydrometeorological Prediction Center for this graphic.
What you see is a prediction for the total rainfall in inches between 8 AM Eastern Daylight Time Saturday and 8 AM EDT on Thursday (in other words – a 5 day total forecast). Already, since this was released, the feared 15″ of rain in the New Orleans area seems highly unlikely due to dry air from Texas being drawn into the system. For ease in reading, left click the image two times independently for full enlargement.
Below is a “cut and paste” from the National Hurricane Center’s report for the first day of the hurricane season, 2011. There is a low pressure system in the Atlantic now making a beeline for my part of Florida and expected to be here around 1 PM. Item 1 below is the discussion of that system. At the very end of this posting you will find a link to the page from which this information was cut. If the graphic you first see is not the satellite image, just left click on it and it should change for you.
My daughter is visiting from New Mexico and this is the day that she and I were to have gone sailing. However – that activity has been canceled and my “little girl” is sleeping in. There was a time in my life when I was more daring and would have gone out anyway – working hard to strategically find safe shelter and counting on lots of luck. But now in my 72nd year I am one to err on the side a caution. The aluminum mast supported by a steel fore-stay and two steel shrouds all serve as excellent lightning attractors. I do not wish for my daughter (or myself for that matter) to become a “crispy critter.” The fun is not worth the risks. So we will find something else to do. The tiny red dot on the image below approximates where I live in Florida and the system is traveling toward the west-southwest. Left click on the image to enlarge.
From my point of view, this is a fitting “sign” that our hurricane season this year is likely to be a busy one. The post that follows this one will link you to a description of the NOAA summary of this years forecast.
ZCZC MIATWOAT ALL TTAA00 KNHC DDHHMM TROPICAL WEATHER OUTLOOK NWS NATIONAL HURRICANE CENTER MIAMI FL 800 AM EDT WED JUN 1 2011 FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO... 1. A SMALL AREA OF LOW PRESSURE LOCATED ABOUT 200 MILES EAST OF JACKSONVILLE FLORIDA IS MOVING WEST-SOUTHWESTWARD AT AROUND 20 MPH. THE LOW CONTINUES TO PRODUCE A CONCENTRATED AREA OF SHOWERS AND THUNDERSTORMS...AND ENVIRONMENTAL CONDITIONS ARE MARGINALLY FAVORABLE FOR SOME DEVELOPMENT OF THIS SYSTEM BEFORE IT MOVES OVER NORTHERN FLORIDA LATER TODAY. REGARDLESS OF DEVELOPMENT...THIS DISTURBANCE COULD PRODUCE LOCALLY HEAVY RAINFALL AND STRONG GUSTY WINDS OVER PORTIONS OF THE FLORIDA PENINSULA. THERE IS A MEDIUM CHANCE...30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. FOR ADDITIONAL INFORMATION ON THIS SYSTEM...PLEASE SEE PRODUCTS FROM YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE. ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS. TODAY MARKS THE FIRST DAY OF THE ATLANTIC HURRICANE SEASON...WHICH WILL RUN UNTIL NOVEMBER 30. LONG-TERM AVERAGES FOR THE NUMBER OF NAMED STORMS...HURRICANES...AND MAJOR HURRICANES ARE 11...6...AND 2...RESPECTIVELY. THE LIST OF NAMES FOR 2011 IS AS FOLLOWS: NAME PRONUNCIATION NAME PRONUNCIATION ------------------------------------------------------------- ARLENE AR LEEN- LEE LEE BRET BRET MARIA MUH REE- UH CINDY SIN- DEE NATE NAIT DON DAHN OPHELIA O FEEL- YA EMILY EH- MIH LEE PHILIPPE FEE LEEP- FRANKLIN FRANK- LIN RINA REE- NUH GERT GERT SEAN SHAWN HARVEY HAR- VEE TAMMY TAM- EE IRENE EYE REEN- VINCE VINSS JOSE HO ZAY- WHITNEY WHIT- NEE KATIA KA TEE- AH THIS PRODUCT...THE TROPICAL WEATHER OUTLOOK...BRIEFLY DESCRIBES SIGNIFICANT AREAS OF DISTURBED WEATHER AND THEIR POTENTIAL FOR TROPICAL CYCLONE FORMATION DURING THE NEXT 48 HOURS. THE ISSUANCE TIMES OF THIS PRODUCT ARE 2 AM...8 AM...2 PM...AND 8 PM EDT. AFTER THE CHANGE TO STANDARD TIME IN NOVEMBER...THE ISSUANCE TIMES ARE 1 AM...7 AM...1 PM...AND 7 PM EST. A SPECIAL TROPICAL WEATHER OUTLOOK WILL BE ISSUED TO PROVIDE UPDATES ...AS NECESSARY...IN BETWEEN THE REGULARLY SCHEDULED ISSUANCES OF THE TROPICAL WEATHER OUTLOOK. SPECIAL TROPICAL WEATHER OUTLOOKS WILL BE ISSUED UNDER THE SAME WMO AND AWIPS HEADERS AS THE REGULAR TROPICAL WEATHER OUTLOOKS. A STANDARD PACKAGE OF PRODUCTS...CONSISTING OF THE TROPICAL CYCLONE PUBLIC ADVISORY...THE FORECAST/ADVISORY...THE CYCLONE DISCUSSION... AND A WIND SPEED PROBABILITY PRODUCT...IS ISSUED EVERY SIX HOURS FOR ALL ONGOING TROPICAL CYCLONES. IN ADDITION...A SPECIAL ADVISORY PACKAGE MAY BE ISSUED AT ANY TIME TO ADVISE OF SIGNIFICANT UNEXPECTED CHANGES OR TO MODIFY WATCHES OR WARNINGS. THE TROPICAL CYCLONE UPDATE IS A BRIEF STATEMENT TO INFORM OF SIGNIFICANT CHANGES IN A TROPICAL CYCLONE OR TO POST OR CANCEL WATCHES OR WARNINGS. IT IS USED IN LIEU OF OR TO PRECEDE THE ISSUANCE OF A SPECIAL ADVISORY PACKAGE. TROPICAL CYCLONE UPDATES ...WHICH CAN BE ISSUED AT ANY TIME...CAN BE FOUND UNDER WMO HEADER WTNT61-65 KNHC...AND UNDER AWIPS HEADER MIATCUAT1-5. ALL NATIONAL HURRICANE CENTER TEXT AND GRAPHICAL PRODUCTS ARE AVAILABLE ON THE WEB AT WWW.HURRICANES.GOV. SIGN UP FOR PRODUCT UPDATES BY EMAIL AT WWW.HURRICANES.GOV/SIGNUP.SHTML...IN ALL LOWER CASE. YOU CAN ALSO INTERACT WITH US ON FACEBOOK AT WWW.FACEBOOK.COM/US.NOAA.NATIONALHURRICANECENTER.GOV. $$ FORECASTER BERG/PASCH NNNN Here is a link to the National Hurricane Center Home Page: http://www.nhc.noaa.gov/gtwo_atl.shtml
By the time you read this, May of 2011 will have ended and the Northern Hemisphere Atlantic, Caribbean, and Gulf of Mexico hurricane season will have begun. The following link will take you to a summary of the NOAA outlook for this season:
Please be prepared if you live in hurricane territory.
The loop above illustrates nicely that a tropical system does not have to be a hurricane in order to cause significant problems including fatalities. TO ACTIVATE YOU MUST LEFT CLICK ON THE IMAGE. Here is what Wikipedia has to say about the 2008 storm: Tropical Storm Fay was a tropical storm and the sixth named storm of the 2008 Atlantic hurricane season. Fay formed from a vigorous tropical wave on August 15 over the Dominican Republic. It passed over the island of Hispaniola, into the Gulf of Gonâve, across the island of Cuba, and made landfall on the Florida Keys late in the afternoon of August 18 before veering into the Gulf of Mexico. It again made landfall near Naples, Florida, in the early hours of August 19 and progressed northeast through the Florida peninsula, emerging into the Atlantic Ocean near Melbourne on August 20. Extensive flooding took place in parts of Florida as a result of its slow movement. On August 21, it made landfall again near New Smyrna Beach, Florida, moving due west across the Panhandle, crossing Gainesville and Panama City, Florida. As it zigzagged from water to land, it became the first storm in recorded history to make landfall in Florida four times. Thirty-six deaths were blamed on Fay. The storm also resulted in one of the most prolific tropical cyclone related tornado outbreaks on record. A total of 81 tornadoes touched down across five states, three of which were rated as EF2. Damage from Fay was heavy, estimated at $560 million.
Here is a link to Wikipedia’s coverage of that storm:
Here is a link to my list of 23 Misconceptions About Hurricanes:
MOST IMAGES ON THIS WEBLOG ENLARGE WITH LEFT CLICKS
This image shows no tropical activity 15 minutes into our 2009 season (not surprisingly) but you can clearly see the clouds development with a stationary front cutting diagonally across the image.
The Atlantic/Gulf of Mexico/Caribbean hurricane season “officially” begins on June 1. The fact that Tropical Depression 1 formed about 4 days before the official season’s beginning is not an indication of an active hurricane season this year. There seems to be no relationship between early activity and the “busyness” of that season. In fact, there is a real possibility that an El Niño event will be strong during what we consider the peak activity period of our season (the approximate middle of the 6 month long period). Eastern Pacific sea surface temperatures have been rising steadily for the last several months pointing to the El Niño possibility. That means is that our 2009 season might be less active than usual if the ENSO comes to fruition. ENSO = El Niño Southern Oscillation. BUT, even if a strong El Niño develops it is no time to let down one’s guard if living in “hurricane country.” 1992 was an El Niño year and that was when Andrew occurred. My house in Homestead was a total loss.
I was extremely well prepared back then (August 24, 1992) but hurricane Andrew slammed in as a category 5. However, we did have a plan and it worked to the degree that no one in my family was physically hurt. Only one window had a small crack but – the roof failed and the damage was almost beyond belief for us. Since Andrew was a relatively dry storm our windows holding firm did make it so that we were able to salvage some valuable items afterwards because the wind did not gut the house.
We stayed in the community and helped rebuild. We had great insurance and our house was reconstructed in one year to a higher standard. During that time we four lived in a 25’ travel trailer that I purchased for that purpose but kept for several years afterwards to use for recreational and educational travel.
If you live in “hurricane country” then you have choices. Some of us have more choices than others but you should at least have a plan that is clearly articulated to and understood by each member of your household. Shall you be well prepared or do you choose to become a potential victim who is dependent upon others almost immediately after a storm?
I urge you to follow to the best of your ability those preparation suggestions made by your local and federal agencies. Some of us are more fortunate than others in what we are able to do to protect our dwellings – that is, those of us who are lucky enough to have a place we call home.
In my new post-retirement community and in neighboring communities (Citrus and neighboring counties) I see what I consider to be real paradoxes or, at the very least, some irony. I’m reminded (but to a somewhat lesser degree) of one of my Homestead neighbors who drove a Mercedes while his wife drove a BMW; they owned a very large boat moored at a dock in nearby Biscayne Bay, an ultra-light aircraft and a twin Cessna – yet they had no window protection of any sort for their home. I speculate that it was not a matter of the cost of such protection but more a matter of priorities and life style with perhaps a little measure of denial thrown in.
Some people in my part of Florida feel that by being inland they have some sort of immunity to the ravages of hurricanes. Yes – it is an advantage being inland, especially if on high ground but it does not offer any guarantees. Most deaths in hurricanes (on the average) are due to high water and being away from the storm surge zones and areas prone to flooding from the storm’s downpours makes for a safer situation – generally speaking. But, high winds can play havoc particularly when items become projectiles in the wind. It is a fact that if the wind velocity doubles, the force it exerts upon a surface it is striking at right angles quadruples! People in my part of Florida experienced a lot of activity if they were here in 2004 but the wind velocities were luckily relatively low. Only modestly higher wind velocities would have produced exponentially greater force and far greater damage. Furthermore, tornadoes and microbursts occur within hurricane bands and neither have a preference for locations near the coast.
Come early August we will have been in our new home for four years. Our first major purchase when moving in was window and door storm protection. We had tended to that “need” before we were even set up with a cable connection for our televisions and computers. For the first two years that we were here I participated in a number of hurricane expos as the “hurricane resource person” on site. There were expo participants who were in the business of selling, fabricating, and installing storm protection to homes and businesses. Most visitors were there to learn about hurricane safety and hurricane protection. But one particular type of visitor seemed to come to these expos in order to exercise their debate skills on the pros and cons of storm protection for windows and doors. I was amazed at times by the level of denial and warped rationalization that I witnessed. Some argued that they refused to concern themselves with such matters and would just let their insurance take care of it for them. There was little if any consideration for how they would deal with losses of personal items, safety issues if they were not to evacuate, safety issues if they were to evacuate, where they would go if they did evacuate in time, and how they would handle matters when they returned if things were torn all to hell! I am convinced that some of the men I talked to felt that it was a manly thing to face a storm raw without preparation – even though in some case it meant leaving their house mates far more vulnerable than necessary. To my mind, they had it backwards – a real man takes care of his own and is available to help others as well.
I can testify, by experience, that the trauma of a storm itself often does not compare to the trauma of the immediate aftermath and rebuilding. Looting, for example and other forms of predatory behavior can occur. In heavily damaged areas the majority of those who come to help are good people with good intentions but there is one whole class of “helpers” who are there to take victims for a ride they will never forget. In South Dade County, where Andrew first struck the U.S.A. the divorce rate just about doubled for the next few years. Stress and anxiety were on a very high level.
So – please think in terms of the big picture when a hurricane visits – not simply the weather event itself. Think in terms of what you’ll do if you lose electricity for several days and how you will fare food-wise if you need to go for a week or more without provisions and how you’ll communicate. Cell phones go out of commission when the transmission and relay towers are damaged. Then there are the special needs people who absolutely must make arrangements for care in the event of a serious storm.
Please be prepared to the best of your ability. If you later consider all of that planning and work to be for naught because no hurricane occurs in your region – there will be more seasons to follow for which you will again be ready and if, near the end of the season, you have a box full of “emergency food” there are surely some places near where you live to donate it to the needy. After all, the end of the official hurricane season (November 30) and Thanksgiving (November 26) are pretty darned close to each other.
Here is this season’s list of names; tropical cyclonic systems will receive names in order from this list once they reach tropical storm intensity; tropical storm sustained winds fall in the range of 39 mph to 73 mph; of course they retain their names if they become hurricanes (74 mph or more):
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What so many have been reluctant to say – probably being extra cautious because nothing is certain at this time – was finally printed in yesterday’s Wall Street Journal. In my first posting about this terrible aircraft accident I suggested that if icing was indeed the problem – the accident should never have occurred. Now – it is beginning to look as though the “reaction” to icing might have been incorrect causing the aircraft to immediately stall.
Please be mindful of the fact that the investigation of this accident is still in a very early stage. Here is a link to the WSJ article:
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The cause of last Thursday’s terrible airplane crash near Buffalo, New York may never be know for sure. In any case, such investigations take many months. There was a brief period of time when there were some significant doubts as to the role of icing in the accident – partly due to the embryonic stage of the investigation hindered by the complexities of carefully sorting debris of the aircraft and the house from the remains of the victims. What a difficult job that must be.
Yesterday and today there have been more indications that icing was responsible. If anything accurate can be said about the nature of the environment which produces icing conditions it is that it is fickle. Just as the surface has its own micro-climatology, so do clouds. It appears to me that the plane that crashed must have entered an icing environment which might have been severe. There is also a possibility of some form of mechanical and/or instrument failure. The final determination could very well point to a combination of unfortunate happenings.
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THE HYDROLOGIC CYCLE, A CLASSICAL TOPIC
IN NATURAL SCIENCE COURSES
I’ve taught the hydrologic cycle many times in geology, meteorology, physical oceanography and environmental science classes. It’s always been a pleasure but I’ve never had enough time. All of these were college courses and in almost every case the text book covered the subject adequately. However, the manner in which water moves and changes in our natural environment is so very interesting that a few pages in a text with a traditional drawing and an hour lecture from me simply does not do the subject justice. Water is such a remarkable compound – I can’t find the words to explain how very interesting it is and how mysterious it can be at times considering the amount of scientific attention it has received through the years. There is still so much to learn.
So, it is with excitement that I look forward to a 6-hour course that I am scheduled to teach in May to the Senior Institute enrollees at Central Florida Community College. In 37 years of full-time college teaching (and 4 years part-time) I never had the opportunity to devote so much time to the subject. The method I intend to use is my own “idea” but surely it has been done before – that is, to follow water step-by-step as it goes from one phase or one environment to the next. My presentation won’t be a journey without side trips and backtracking. There are multiple manners in which water can transform and/or move with interesting little anomalies along the way. With 6 hours to utilize I will be able to discuss aspects that were only fleetingly mentioned in my previous hour-long presentations e.g.: Capillary action, deposition, glacial calving, influent groundwater movement, juvenile water, super-cooled droplets, and much more.
SUPERCOOLED CLOUD DROPLETS AND ICING
I feel fairly certain that some people who read this have had the experience of having rain freeze upon impact with their vehicle’s windshield. Some would assume that the freezing occurs because the windshield is so very cold. That is usually not the case. Instead, the liquid droplets were probably at a temperature well below “freezing” and the impact with the windshield itself triggered the instant freezing. Hopefully, the “defrosting” vents can keep the windshield warm enough so that the ice can be quickly cleared. Now, imagine what it must be like if the surfaces being iced are the windshield and wings of your aircraft in flight – as well as other aircraft surfaces (e.g. propellers, fuselage, horizontal stabilizers)!
Today, February 15, 2009, the mere thought of super-cooled droplets hauntingly reminds me that in addition to the marvelous beauty of water’s multifaceted journeys and transitions through our natural environment, there are some insidious elements that can become deadly in this modern world. Of course, I’m thinking specifically of the recent terrible aircraft accident responsible for 50 fatalities near Buffalo, New York.
For a short while since the accident it appeared that icing might have been the culprit or perhaps a contributing factor in causing the aircraft to make its sudden rapid descent (apparently almost immediately after the application of flaps). At the time other aircraft in the vicinity were reporting icing. HOWEVER, AT THE TIME OF THIS WRITING, NEWS RELEASES HAVE INDICATED THAT THE NATIONAL TRANSPORTATION SAFETY BOARD CLAIMS THAT ICING APPEARS NOT TO HAVE BEEN A FACTOR. The changing of the airfoil’s shape upon flap engagement might have triggered the rapid descent – an apparent stall leading to a flat spin. That would indicate either insufficient air speed at the time of flap deployment or some type of catastrophic failure. SINCE MANY AVIATION ACCIDENTS HAVE BEEN CAUSED BY ICING – AND IT WILL REMAIN A PROBLEM FOR AIRCRAFT FOR A LONG TIME TO COME, I SHALL CONTINUE.
When icing was being blamed, I suspected that some critical errors might have been made in the cockpit. At best, my notions were intuitive – or, on the other end of the spectrum, unfair during such an early stage in the investigation. Nevertheless, a surprising amount of information has been made available during this embryonic phase – partly due to the fact that the flight recorders are advanced models and they were in very good shape. There is no need for me to dwell on factors that can cause a plane to become unstable when icing occurs – suffice it to say that airfoils lose “lift efficiency” quickly when ice buildup changes their shape and of course the weight of the ice accumulation can also be a huge factor. I do not know what kind of air speed indicators are installed on that type of aircraft but I do know that icing can cause false readings on some types. Icing can also cause problems at air intakes and oil cooler intakes of some aircraft.
IN THE FIRST PLACE?
The cause of the icing is a surprise to most people. Though icing can occur on a plane’s very cold surface when it descends into “warm” clouds whose temperatures are above freezing, the vast amount of problematic icing occurs when the liquid droplets themselves are below what we traditionally consider freezing temperature. These droplets consist of what is called supercooled liquid water (SLW). Water in cloud droplets can get as cold as about negative 40 degrees Celsius (which is the same as negative 40 Fahrenheit) without freezing.
When liquid water freezes (box 3 to 4 in the illustration above) the water molecules align in a crystalline fashion. But in order to do so they need one of two things: 1) either a freezing nuclei whose surface acts as a template to initially “show” the molecules how to (or trigger the molecules to) line up, or 2) some molecules themselves must be jolted (or jiggled) such that for at least an instant they are arranged so they can act as a template or model for the rest to follow. The likelihood of such alignment occurring in undisturbed droplets is slim. This would not be true of most fresh water at the surface, such as in lakes because there are microscopically-sized particles available in the water to act as templates. On the other hand, water that has condensed and remains in the air is very “clean” by comparison.
An aircraft flying though supercooled cloud droplets causes considerable rapid stirring to set the stages for freezing upon impact with that aircraft – just as supercooled raindrops freeze upon impact with trees and suspended wires in those notorious, damaging ice storms.
The first three links below show convincing demonstrations of liquid water freezing as a result of hexagonal ice crystal seeding. The ice crystals provide the template which “shows” the liquid water what to do in order to become solid. In the third example when the water freezes and builds up a small mound on the wooden post, I suspect that the split second ideal alignment of some water molecules (while pouring) provoked the freezing.
In this 4th example you will see that a jolt causing a sloshing of the water in the small amount of air space at the top of the bottle allows for enough water movement so that for an instant a hexagonal orientation occurs among some molecules causing a very rapid “follow the leader” freezing all the way down to the bottom of the bottle.
Just as condensation and deposition give off heat, freezing is also exothermic. This is probably why some of the water remains in the liquid state. If the SLW is not very much colder than “freezing” temperature, the heat given off during freezing will cause the remaining liquid to acquire enough heat to teeter over to the liquid side.
Use the search term “supercooled water” on YouTube.com and you will find many other video demonstrations.
WHEN WATER FREEZES IT EXPANDS, BECOMING LESS DENSE. THIS EXPLAINS WHY SOLID WATER FLOATS UPON LIQUID WATER.
If you compare box 3 and 4 in the illustration in this post, you will see why water expands and becomes less dense upon freezing. To establish the hexagonal grid necessary for ice, the molecules can’t be as close together as they were when they were in the cold liquid stage.
Information on supercooled liquid water would have eventually been posted here if the Continental Express Flight 3407 disaster had not occurred. It is regrettable that the accident played a role in my posting this information at this time. I offer my sympathy to all who have broken hearts over the loss of a loved one and all others adversely effected.
Finally, the information in this post about SLW and icing merely scratches the surface compared to that which is known. But, that which is not understood is formidable.