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The Hurricanes Return--1995-2005
Hurricanes come in cycles. A casual glance at a list of active hurricane seasons shows clusters of activity in the 1880s-1890s and 1920s-1960s, while the early twentieth century and the 1970s, 1980s, and early 1990s look relatively calm. Another active period started in 1995 and continues today.
Dramatic economic growth, immigration, increasing longevity, and other factors coincided with the hurricane downturn of the late 1960s to mid-1990s. The effect can be seen throughout the coastal zone. Would 18 million people be living in Florida today if hurricanes had continued coming at the rate they occurred in the late 1940s and in the last two years? I wonder.
Unfortunately, the people in government with the responsibility for seeing that citizens are safe during disasters were (and are) not very good students of history. Most coastal areas, including the state of Florida, were developed without regard to the hurricanes of the past and without protection from the hurricanes to come. Thus, future disasters are guaranteed.
Hurricane cycles correlate with the natural fluctuation in the temperature of the ocean.
This chart compares the Atlantic Ocean water temperature to normal. The match with hurricane activity is remarkable. Notice that the late 1800s and the period from the late 1920s to the late 1960s show warmer than normal temperatures. They were active hurricane periods as well. The swing in temperature is only about plus or minus one degree Fahrenheit, but the amount of energy that slight difference makes spread out over the entire Atlantic Basin is significant. See "Global Warming and Hurricanes," page 74.
Hurricane Season 2005
Every hurricane has its own personality, and every hurricane season does as well. Anytime there are a lot of landfalling storms, let alone a record-setting season like last year's, lessons abound--big and small. In my opinion, the biggest lesson of the hurricane season of 2005 was: The worst does happen!
In case after case people suffered and property was destroyed because someone--a governmental body or official, a business owner or a private citizen--decided to ignore hurricane history, ignore hurricane research, and hope for the best. Thus the lesson. Hoping does not hold back wind and water.
The two most remarkable storms of 2005 were Hurricanes Katrina and Wilma. That's not to ignore or discount the effects of Dennis, Emily, Ophelia, Rita, Stan, Gamma, and the rest. In a normal hurricane season, any one of those storms would be memorable. But Katrina and Wilma rose above the pack in this extraordinary season of storms.
An easy-to-forget aspect of the 2005 season is that none of the record-setting hurricanes formed in the deep tropics. Through history, most of the "great" hurricanes have formed well east of the Lesser Antilles. From there they have time to organize and gain strength. The fact that the traditional breeding ground for big, powerful hurricanes was not fertile in 2005, and yet fifteen hurricanes formed, gives us pause. See "Hurricane Season 2006," page 15.
Researchers still haven't determined for sure why the deep tropics were shut off in 2005. A reasonable explanation might have to do with the "waviness" of the weather pattern around the earth. Rarely are all parts of the Atlantic Basin in a favorable mode for storm development at the same time. Normally, when one part is favorable, other parts are not. In 2005, however, the weather pattern in the Gulf of Mexico and the western Atlantic was ideal for strong storms from June to December. Perhaps the favorable area just never shifted, so the eastern Atlantic stayed in an unfavorable mode. More research remains to be done.
Thursday, August 29, 2005--Hurricane Katrina
Katrina was a hurricane catastrophe . . . in southern Mississippi. In Louisiana, it was a healthy hurricane hit . . . and a levee design/engineering/maintenance/operation debacle . . . compounded by a FEMA fiasco . . . that led to human suffering on a scale that we had not seen in the United States in modern times. Everyone involved, from Washington, D.C., to Louisiana, should be ashamed and embarrassed. We should all be disgusted with our governments.
Katrina's winds in New Orleans. There is very little, if any, reason to think that most of New Orleans experienced more than a category 1 hurricane. For the city it was nowhere near a historic hurricane event. Here is the evidence:
• The only wind in New Orleans over category 1 strength was measured on the far east side of the city, and it was 96 mph, the lowest number in the category 2 range. All of the other measurements--although there weren't many--were low-end category 1 or tropical storm force.
• An anemometer in the middle of Lake Pontchartrain that survived measured a peak sustained wind of 78 mph. While this may not have been the highest wind over the lake, it should be reasonably representative. And it's low-end category 1.
• The water did not top the Lake Pontchartrain levee. Originally designed for a category 3 storm surge, the levee at its existing height would likely only withstand a category 2, according to research by a group at Louisiana State University. That levee, along with all of southern Louisiana, is sinking. So the evidence is that the storm surge rose to less than category 2 levels.
• The wind rating of the roof shingles on most of the houses in New Orleans was 60 mph. Most of the shingles stayed on.
• A rough estimate of the wind on the left side of the storm (the New Orleans side of Katrina) is 93 mph.
Follow me now. There are two components to the maximum wind speed in a storm: the intrinsic wind of the counterclockwise circulation and the contribution from the forward movement of the system. As Katrina moved north toward the Gulf Coast, the total wind speed on the right side included the forward speed of the storm. The wind speed on the left side was the intrinsic wind in the storm minus the forward speed. Therefore, the wind on the left is the right-side wind (the maximum wind) minus twice the forward motion.
So, as an approximation, the maximum wind on the left side--the New Orleans side--of Katrina was at most 93 mph, a strong category 1. It's a rough estimate, to be sure, but the calculation adds to the case that the winds were not the cause of the catastrophe.
Katrina's storm surge in East New Orleans. New Orleans was subject to storm surges coming from two directions, each caused by two different factors. To understand what happened during Katrina we have to look at them separately.
To the east side of the city, a massive storm surge was generated by Katrina's winds, which the day before, had been 165 mph. That water was forced into the "corner" formed by the southeastern Louisiana and southern Mississippi coasts and then up the Mississippi River-Gulf Outlet Canal (the MR-GO) toward the city. Under the pressure of this water, the levees on both sides of the canal failed, inundating New Orleans East and St. Bernard's Parish. The high-speed water continued west into the Industrial Canal, where the levees also collapsed, putting the Lower Ninth Ward under water.
The MR-GO Canal had previously been identified as a threat to the eastern part of the city. As water funnels into a narrow canal the power of the water is accentuated, an extremely bad design in a storm-surge prone area.
Many areas on the eastern side of New Orleans would have flooded even if the levees had not failed. There is a debate about whether the flooding would have as bad--it probably would not have been--but it would have been devastating and deadly in any case. It has been well known for years that this is the most vulnerable part of the city from a storm on Katrina's track.
Katrina's storm surge from Lake Pontchartrain. Late in the morning of August 29 Katrina was moving ashore in southern Mississippi. At that time, the northerly winds on the left side of the circulation were pushing the lake water toward New Orleans, into the north-opening drainage canals, and deep into the city. Apparently, the inflowing water put more pressure on the flood walls than the clay layer holding the bottom of the walls could handle. The walls collapsed, with devastating results for the low-lying, northern part of the city.
The exact sequence of events is still not clear, but the flooding should not have happened. As noted, the winds pushing the water were likely in the category 1 range. The levees appear to have been built to their design specifications. The whole thing just looks like a bad idea. There are big pumps that take water out of the city and push it into these canals and toward the lake--against a storm surge driven by a north wind. How could this ever work? The U.S. Army Corp of Engineers, the designers of the levee system, is still investigating, but the preliminary indication is that the design was at fault.
The new plan is to block the end of the canals at the lakefront to keep the surge from ever coming into the city. This seems like such a practical solution to an obvious problem, it's amazing it was never brought up in any seminar or conference I ever attended at which the New Orleans hurricane problem was discussed. Far more explanation is going to be required from the experts as to how this could have been overlooked.
Katrina in Mississippi. In Mississippi, Katrina was a historic hurricane. The storm surge exceeded the high-water mark from Hurricane Camille in 1969, the previous benchmark storm for that region. While Katrina was nowhere near as strong as Camille, it had been a category 5 in the Gulf and put a lot of wave-producing energy in the water. And, more importantly, it was a much bigger storm in physical size. Storms with a large "radius of maximum winds" generate larger storm surge. See "Storm Surge," page 77.
Any hurricane that produces a twenty-to-thirty-foot storm surge is going to do major damage at the coast. But at least some of the blame needs to fall on the officials in Mississippi who allowed such expensive infrastructure to be built where it was guaranteed to be ruined by any significant storm. When it came time to authorize casino gambling at the coast, Hurricane Camille apparently escaped everybody's memory. It's another example of government creating a policy that's built on wishing and hoping. Government should not roll the dice, so to speak. We can only hope that, once and for all, this will be enough to indelibly make the point: The worst does happen.
Mississippi building codes. There is a battle under way in the spring of 2006 over a building code for the state of Mississippi. Many construction-industry groups are urging the governor and the legislature to pass a minimum statewide code. Mississippi and Alabama are the only states in the most hurricane-vulnerable region that do not have statewide codes.
The resistance to legislation that would protect lives is, in my opinion, impossible to justify. Mississippi doesn't even have any standards to protect people from fire, and there are more fire deaths there than in any other state by far. The proposed code is only half-baked: It's aimed at the southernmost counties. But it's a start, and a sad commentary on the state of government.
A strong building code is in the public interest. When people are injured because a poorly constructed house collapses, rescue personnel often have to risk their lives to help them. When buildings come apart and spray debris all over the neighborhood, damage is multiplied and public money is needed to clean up the mess.
To live in the north, you need big heaters and lots of insulation. Along the coast you need hurricane protection. There's no excuse for politicians standing in the way of safety.
FEMA and Michael Brown. In my opinion, fired FEMA director Michael Brown did not get a fair shake. His position and power in the hierarchy of the newly created Department of Homeland Security-FEMA structure didn't give him the authority that the position previously had. He was in a bureaucratic box.
Still, a more courageous and more experienced emergency manager might have walked up to a microphone the day that Katrina hit and pointed a finger at the director of Homeland Security and the president and said, "People are going to die here if you don't do something now!" If he was as frustrated by the bureaucratic bungling as it seems he was, why wasn't he pointing with all ten fingers at once and screaming at the top of his lungs? Instead, he played the good soldier and tried to work within a dysfunctional system--that he had been a part of for years.
FEMA was a model agency before it was folded into the Department of Homeland Security in 2003. The move, per se, wasn't the problem. If the agency had been left intact to do its job, the structural change would not have been disruptive. But people without emergency management experience made decisions that gutted FEMA's ability to quickly and properly respond to natural disasters. DHS is, essentially, a police agency, cops looking for bad guys. FEMA and emergency management are different animals. In large measure that was and is the problem.
The fact that President George W. Bush, DHS Secretary Michael Chertoff, and the head of the U.S. Army Corps of Engineers, General Carl Strock, were completely misinformed and saying ridiculous things for days and weeks after the disaster is frightening. These people know when a pin drops in Afghanistan. How can they not know when a levee breaks in New Orleans? The evidence says that the communications and operational infrastructure of the federal government has broken down. We should all be very concerned.
Monday, October 24, 2005--Hurricane Wilma
Wilma in the Caribbean. By the time Wilma came along in late October, hurricane weariness had set in. Still, the storm got our attention in the eastern Caribbean when Air Force Reserve Hurricane Hunters measured the lowest barometric pressure ever seen in the Atlantic Basin (the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico): 882 millibars beat the 888 mb measured in Hurricane Gilbert in 1988. Amazing.
And it all happened in a flash! In the twenty-four hours between 2:00 a.m. EDT on October 18 and 2:00 a.m. EDT on October 19, Wilma went from a 70 mph tropical storm to a 175 mph, category 5 hurricane. The National Hurricane Center now estimates that Wilma reached its peak intensity around 8:00 a.m. on the nineteenth, 185 mph. The lowest pressure was also measured at that time, and the pressure was still falling. Incredibly, it's possible the pressure dropped lower after that measurement was taken.
The extraordinary wind speeds were possible because Wilma developed an eye that was only about two miles across. In general, the smaller the eye, the stronger the winds. The physical principle is called "conservation of angular momentum." It's the same thing that causes a figure skater to spin faster by pulling his or her arms in toward the body.
This rate of strengthening has never before been seen in the Atlantic Basin. In fact, no storm in the record book has ever strengthened at a rate even close to Wilma's. Also, the staff at the National Hurricane Center noted that they were not aware of an eye ever being seen as small as two miles. When I read the observation from the aircraft, I thought it was a mistake.
Wilma in South Florida: After the storm bashed the Yucatán Peninsula, the National Hurricane Center forecast showed a track across South Florida. That's when a lot of amateur meteorologists in metropolitan southeast Florida decided: (a) a storm coming from the Gulf can't be too bad, and (b) we never get two storms in one year and we've already had Katrina. Wrong and wrong again. It was a painful, aggravating mess for hundreds of thousands of people from Palm Beach County to the Florida Keys--and an extreme inconvenience for the rest of the five million-plus residents.
Hurricane Wilma turned out to be the fifth most expensive hurricane in U.S. history. Yet a good part of the metropolitan Miami-Fort Lauderdale-West Palm Beach area never saw winds higher than category 1. In the National Hurricane Center's analysis, some areas did experience category 2 winds, but most of the category 2 winds appear to have been in gusts. Because of the dense population right along the coast, the effects were magnified. Thus, the second big lesson from 2005:
ANY HURRICANE MOVING OVER A MAJOR METROPOLITAN AREA WILL CAUSE PROBLEMS THAT WILL EXCEED THE ABILITY OF THE GOVERNMENT TO MANAGE THEM.
Government response to Wilma. You hear politicians today patting themselves on the back on how well they did in a "very difficult situation." If a "barely category 2" storm is a very difficult situation, what does that make a category 3 or 4? "Unmanageable with the current system" is the only answer.
In a major city there are too many people, with too many difficult problems for the current underfunded, underdeveloped emergency management system to handle. FEMA's emasculation has only made the situation worse. The numbers tell the story. If government could solve the major problems of 99 percent of the population in three days (which would never happen, but let's just imagine), more than 50,000 people in metropolitan Miami-Fort Lauderdale-West Palm Beach would be abandoned. And these are the people who likely have no transportation, do have health issues, and are the least able to take care of themselves. Tens or hundreds of thousands of people would be hurt and lost. It's a monstrous public safety issue.
The entire system needs to be revamped. Mickey Mouse emergency management systems with learn-as-you-go politicians making critical decisions on the fly need to be scrapped and professionalized. Politicians who show up and take charge at the time of an emergency make bad decisions because (a) they have not taken the time to be trained in emergency management where, theoretically, all imaginable scenarios are thought out ahead of time, and (b) their instant decisions on what to say and do are often driven by political (translate: wishful) thinking.
Building code flaws revealed. Throughout this book you'll see references to the mighty South Florida Building Code in use in the Miami-Dade and Broward Counties. It is a very strong code, the strongest in the country against hurricanes. But Wilma pried it open and showed its weaknesses.
First, roofs blew off, and all kinds of bad things happened, mostly in buildings built before the code. Some affordable system of retrofitting existing structures is essential, or a category 3 hurricane is going to be cataclysmic.
Second, numerous high-rises built to the current code suffered severe damage. Nobody expected that to happen. One flaw in the code is the idea that "large missiles" (big hunks of debris) are only a threat on the lowest three floors of a structure. Now we know better. Because of the way winds swirl in every direction around high-rises, the entire building needs to be resistant to debris impacts, not just the lowest thirty feet.
Correcting this flaw is an expensive and frustrating reality that will affect every new building. At least Miami-Dade and Broward Counties' governments are interested in fixing the problems and doing it right, which is more than you can say for the rest of Florida and most of the hurricane coast.
See "How I'd Do It Better," page 225.
Sunday, July 10, 2005--Hurricane Dennis
Dennis's records. Never before in the record book had a hurricane as strong as Dennis formed before August. (See "Emily," page 13.) On July 8, just before making landfall in south-central Cuba, the maximum sustained winds peaked at 150 mph--high-end category 4 strength. After weakening over Cuba, Dennis restrengthened dramatically over the Gulf of Mexico. On the morning of the tenth the maximum winds were up to 145 mph as the storm headed toward the Pensacola-Mobile area. Fortunately, Dennis weakened right before coming ashore, so the estimated maximum winds were 120 mph at landfall, but no observations higher than 100 mph were reported.
Dennis's storm surge. Dennis came ashore about thirty miles east of where Ivan hit in 2004, but was not as strong or as damaging. Still, the storm surge in the western Florida Panhandle was 6 to 7 feet, enough to wash over the barrier islands near Pensacola and do significant damage, especially in Navarre Beach. The surprise, however, occurred in Apalachee Bay, 180 miles to the east. A 6 to 9 foot storm surge there swamped the town of St. Marks and the surrounding area. The surge was approximately double what was expected. A phenomenon called a "trapped shelf wave" was responsible. Basically, in the shallow water above the very wide continental shelf along the west coast of Florida energy propagated north. Even though the shelf was on the edge of the storm, the "ducting" caused by the shelf had an enhancing effect.
Saturday, July 18, 2005--Hurricane Emily
Late on Thursday, July 16 Hurricane Hunters found category 5 winds in Hurricane Emily when the center was about 115 miles southwest of Jamaica. It was a very close call for that island. This was the first and only category 5 hurricane ever seen in July. As with Dennis, the extremely warm Caribbean and Gulf water seems to have been a factor in creating these July storms of record strength. A category 3 version of Emily came ashore over Cozumel on Mexico's Yucatán Peninsula early on the twentieth, an area that would be devastated by Hurricane Wilma three months later.
Saturday, September 24, 2005--Hurricane Rita
Southeast Texas and southwestern Louisiana got the short end of the hurricane stick in 2005. When Rita veered north from Houston, the consensus was that "it could have been a whole lot worse." Well, that's certainly not the sentiment in Port Arthur, Texas; Lake Charles, Louisiana; and their environs. A 15 to 18 foot storm surge pushed water thirty miles inland in some spots. Towns along and just north of the Gulf in southwest Louisiana were essentially destroyed. The coastal area there may never be the same. Winds were estimated at 115 mph along the coast at landfall, but weakened quickly inland.
Rita in the Gulf. Three days before coming ashore at the Texas-Louisiana border, Rita went through a spectacular rapid intensification phase similar to what we had seen with Katrina a month before and would see with Wilma a month later. At 11:00 p.m. EDT/10:00 p.m. CDT on the twenty-first, Rita had maximum sustained winds estimated at 180 mph and a central pressure of 895 mb. That was the third lowest pressure ever measured in the Atlantic Basin (now it's the fourth).
At that time, the forecast cone predicted a landfall somewhere between Corpus Christi and central Louisiana. The focus was on the Houston-Galveston area, however, because of the potential for a cataclysmic direct hit there. In actual fact, the landfall odds were about equal over the entire northern half of the Texas coast, and not significantly lower in western Louisiana.
Houston evacuates. In the Houston metropolitan area it was clear the hurricane plans in place were inadequate and unrealistic. Millions of people tried to evacuate at the same time. It was chaos. You might have heard that the problem was caused or exacerbated by people who did not live in the evacuation zone leaving when "they didn't have to." Well, yes and no. The problem is that most Houston-area homes don't have shutters and the structures are of questionable strength even if they do. Should people stay in Houston-quality homes in the face of a category 3 or 4 hurricane? My advice would be, "Get out!"
The only solution in metropolitan Houston is a crash program to build safe rooms within existing homes. Governments there have allowed this massive metropolitan area to be built with substandard homes, given the hurricane threat. There's no going back and rebuilding correctly. But people can strengthen a closet or a small room so they will be safe at home during a storm.
Tuesday, October 4, 2005--Hurricane Stan
Disastrous flooding occurred in Central America at the time Stan made landfall with 80-mph winds ninety miles south of Veracruz, Mexico. Between 1,500 and 2,000 people are reported to have died, most of them in Guatemala. It is not believed that Hurricane Stan was directly responsible for this event. A large low-pressure system to the east of Stan seems to have to been the cause of the flooding.
Copyright © 2006 by Bryan Norcross. All rights reserved.