The search phrase “Hurricane Katrina” returns almost 3.3 million hits on Yahoo, while Google returns 11 million. For comparison, 2005’s Hurricane Wilma garnered 243,000 hits. 1983’s Hurricane Alicia 305,000 hits. Hurricane Andrew, in 1992, devastated the town of Homestead, Florida and nearly wiped Homestead Air Force Base off the map — 500,000 hits.
What can I add to the Katrina story that hasn’t been said already? Meteorologically, it’s all been covered. Socially, it’s still being covered. And now that the five-year anniversary of Hurricane Katrina is this Sunday, 8/29 everything already covered is being covered again. I can add my (short) story. And I can add a little bit about how ImpactWeather used Katrina to improve its service by developing an industry-leading storm rating system that is changing how hurricanes are considered.
At the time, ImpactWeather provided the on-air weather service for WWNO-FM, New Orleans. In addition to our daily forecasts, we provided hurricane expertise and commentary for the listeners. As the morning meteorologist and the supervisor of the ImpactWeather Broadcast Team, it was my responsibility to provide frequent and detailed coverage of the storm while setting the tone of the coverage for the rest of the team. Three days from landfall, the forecast shifted from a Florida Panhandle landfall to one on the Mississippi Coast. Two days from landfall, President George Bush declared a state of emergency for most areas of the northern Gulf Coast, including Alabama, Mississippi and most of Louisiana. The day before landfall, New Orleans Mayor Ray Nagin ordered the first-ever mandatory evacuation of the city while city officials established shelters, or “refuges of last resort,” including the Louisiana Superdome — home to the New Orleans Saints.
Though some computer models were suggesting a direct hit for New Orleans and much of the media reported the likelihood of a landfall exactly on top of New Orleans, our ImpactWeather forecast kept the storm east of the city. Our concern was less about the consequences of a direct hit and more about the surge that could overwhelm the levees. This scenario become more evident in the hours before landfall and we continued to report a landfall east of the city and the possibility of the storm surge inundating Lake Pontchartrain and the surrounding waterways. I’ll never forget WWNO’s on-air news anchor saying to me early Monday morning several hours before landfall, “What’s happened to the forecast?!” when I explained how a landfall just east of New Orleans could be worse than a direct hit due to the flooding potential coming into the city from breached levees to the north, as opposed to the surge from the Gulf of Mexico to the south.
What followed has been well chronicled by every media outlet over the past five years. Coverage has been excellent and terrible and everything in between. At ImpactWeather our hurricane experts looked at how Hurricane Katrina was represented as a storm in the days before landfall and during the months after landfall and thought, “There must be a better way.” The better way is the Hurricane Severity Index.
The Hurricane Severity Index (HSI) is not meant to replace the 39- year-old Saffir-Simpson Hurricane Scale (SSHS) scale, but it was acknowledged by not only ImpactWeather meteorologists that the SSHS doesn’t tell the whole story of a tropical cyclone. Ask any coastal resident, not just Louisiana but any coastal resident from Texas to Maine, about the Saffir-Simpson scale and they’ll tell you it’s the hurricane rating system. Perhaps the specifics break down a bit, but most know it’s a 1-5 scale with 5 being the worst or the most powerful hurricane. Most know, too, their own personal “scale” that says they won’t evacuate for less than a 3, most will leave for a 4 and only the hearty or crazy will stay for a 5.
Missing from the Saffir-Simpson is a consideration for the size of a storm. Intensity, yes; size, no. Are all storms created equal? Are all Category 3 storms the same and can the same damage be expected from each? No. Even if the wind speeds are the exact same, a storm with a bigger “footprint” of hurricane-force winds will cause more widespread damage than one relatively confined and compact. What about a broad tropical storm that potentially could bring flooding to thousands upon thousands of square miles? The SSHS does not consider a topical storm. The HSI was created to consider both intensity and size and to provide an index to rate not only hurricanes but tropical storms, as well. Since 2006 the HSI has been in use and the catalyst was Hurricane Katrina.
Not only is Sunday the 5-year Anniversary of the Louisiana landfall of Hurricane Katrina, it is also the 5-year anniversary of the most active hurricane season on record. I did a few more Google searches: “Most active hurricane season,” 456,000. “2010 Hurricane Season,” almost 1.9 million. “Hurricane Severity Index,” 15,700.