May 28 2010
FORT LAUDERDALE—Summer time. Hurricanes. This year, with a very busy hurricane season coming up – according to government and university experts—the National Weather Service wants to set a few things straight.
For nearly 40 years, government forecasters have been describing hurricanes in the dispassionate, clinical terms of engineers and meteorologists.
Now the forecasters have rewritten the guidelines on hurricanes to make the impact of high winds more vivid. And they may end up scaring the daylights out of people.
The forecasters have thrown away terms like minimal, moderate and extensive damage and now starkly warn that even the most modest hurricanes can savagely dismantle mobile homes, shatter windows, rip off roofs, kill and maim. The most severe storms, the new guidelines say, are very likely to leave parts of towns and cities “uninhabitable for weeks or months.”
You already knew hurricanes were bad. But you have never heard it so clearly from weather central. Now the forecasters are saying, enough with restraint, enough with ambiguity. Let’s try telling it like it is.
“This might scare people,” said Bill Proenza, the regional director for the southern United States for the National Weather Service. But, most of all, he said, it might motivate them to put up shutters, tie down lawn furniture and show a little respect for even the lowly Category 1 hurricane which, with winds as low as 74 miles an hour, has done its share of killing and wrecking. Hurricane Katrina, for example, was a Category 1 when it sliced across Florida in 2005 and it wreaked $1 billion in damage.
This could be a terrible hurricane season. The National Oceanic and Atmospheric Administration says that up to 14 hurricanes could develop during the six-six month season from June 1 to Nov. 30 and that as many as seven of them could become major storms. A big hurricane could spread the BP oil spill across a wider swath of the Gulf of Mexico. Federal Emergency Management officials say that as little as several days of heavy rain on the periphery of a hurricane could create a new disaster for the one million Haitians still living in tents after the earthquake in January.
The forecasters worry that the tens of millions of Americans living in the hurricane zone, mostly along the southern coasts, may not be taking hurricanes seriously. One reason more than 1,800 people died in Hurricane Katrina in Louisiana and Mississippi, storm experts say, was that many shrugged when they should have been boarding up their homes and heading for higher ground. The awful memories of Hurricane Katrina may be fading, the forecasters say, especially after last hurricane season when not a single powerful storm made landfall in the United States.
“Complacency is always a problem,” Mr. Proenza said in an interview here during a break in the annual Florida Governor’s Hurricane Conference in late May.
People who are newly arrived in the hurricane zone, those who have been on the fringes of big storms and others who have lived all their lives along the coasts, but never endured a hurricane, are the most likely to ignore storm warnings and end up in trouble, the experts say. “They really don’t comprehend the full potential impact of a hurricane,” Mr. Proenza said.
So after nearly 40 years of referring to hurricanes in low-key generalities, the weather service has decided to try something new. “We wanted to provide a realistic portrait of what winds can do,” said Chris Landsea, the Science and Operations officer at the National Hurricane Center near Miami. Mr. Landsea led a team of experts who rewrote what used to be known as “The Saffir/Simpson Hurricane Scale.” The guidelines are published on Internet sites around the world, distributed by emergency managers and referred to by journalists in their reports. The new guidelines were issued without fanfare in March and revisions were being made well into May.
The new name for the government guide that describes the five categories of hurricanes is “The Saffir-Simpson Hurricane Wind Scale.” Hard to see the difference? One big feature of the new guidelines is what you can’t see.
The whole project got started because complaints had been growing, both among experts and among ordinary Americans, that “The Saffir/Simpson Hurricane Scale” was misleading on storm surge, the wall of water that often slams ashore in a hurricane with the force of a bulldozer and that over the years has killed many more people than wind.
According to Saffir/Simpson, which was introduced in 1972, A Category 3 hurricane with winds of up to 130 miles an hour should create a storm surge of up to 12 feet. Katrina came ashore in Louisiana and Mississippi as a Category 3 hurricane and was pushing a wall of water nearly 30 feet high. Three years later, Hurricane Ike hit the Texas coast as a Category 2 hurricane with a 20-foot-high storm surge, more than three times greater than anticipated by Saffir/Simpson.
The forecasters’ solution was to yank the information on storm surge from Saffir/Simpson. So it is no longer a hurricane scale with guidance on both wind and storm surge. The new Saffir/Simpson deals only with wind, hence the new name, “The Saffir-Simpson Hurricane Wind Scale.” Now, on storm surge, the forecasters are going to be creating tailor-made estimates for each hurricane as it develops, working with a wide range of variables including one of the most important, the shallowness of offshore waters. The shallower the water, the bigger the storm surge.
Forecasters have routinely warned in commentaries that Category 1 hurricanes should not be disregarded and they have been offering their own calculations on storm surge. But their remarks and calculations have been contradicted by storm descriptions in official documents.
Strictly speaking, hurricane experts say, the descriptions were not wrong. But they were not clear either. “The winds in a Category 1 hurricane are about the same as the winds in a severe thunderstorm, a little higher,’’ Bill Read, the director of the National Hurricane Center told me. So in a sense you could say, as the old Saffir/Simpson did, that the winds might cause minimal damage. “But,” Mr. Read said, “the thunderstorm winds might last for one to 15 minutes. The same winds in a Category 1 hurricane last for hours and can have a tremendous impact.” #