Hurricanes past, present and future
By Chip Drago
Mobile Bay Times
Veteran local meteorologist Dr. Bill Williams has good news and bad news for residents of the Alabama Gulf Coast -- Hurricane Ike is gone to Texas or headed that way and not this way, but hurricane season is only at the halfway mark.
Speaking to the Mobile West Rotary Club this afternoon, Williams brought his audience up to date on the meteorology program he founded at the University of South Alabama, the state of hurricane research and historical odds and ends on past hurricanes.
Williams is the director of the Coastal Weather Research Center at the University of South Alabama and coordinator of Meteorology at USA. He founded the USA meteorology program in 1992 with a single student majoring in meteorology. The program now has 114 majors and is the 9th largest meteorology program in the country.
It is only in the past four or five years that hurricanes have surged into the public eye and attracted intense public interest on a broad scale, he said. The advent of a heavy hurricane cycle along with the epochal Hurricane Katrina have made hurricane watching a seasonal spectacle.
Al Gore aside, the frequency and power of recent hurricanes have nothing to do with global warming, according to Williams. He, and most other meteorologists, believe that global warming is a fact, though not necessarily caused by man, but rather by a cycle in the earth's weather pattern.
Williams said hurricane seasons ramp up every so often. As far as intensity, that is difficult to quantify, he said, because modern technology including satellites and inside-the-eye, data-gathering flights did not exist in the 1930's and 1940's. So assessing past hurricanes is cloudy at best, he said.
"Maybe we had (Category) 4's and 5's in the 30's and 40's, but we just don't know," he said.
The records show 21 named storms in 1933, said Williams. However, the actual number may have been 31 but several slipped through unrecorded because of the lack of satellites, he said.
"We just don't know what we don't know," Williams said.
When 27 named storms, too many for one trip through the alphabet, occurred in 2005, many "rushed to judgment" about the cause, assigning blame to some man-induced cataclysm, said Williams. More likely, we are simply in a heavy hurricane cycle, Williams said.
In 2006, hurricane activity shut off like a faucet. An unexpected El Nino was to thank for that respite, said Williams.
El Nino has vamoosed and conditions are back to normal, said Williams, meaning 2008 looks like a year with 18 named storms.
Like sharks, hurricanes are fascinating, even idiosyncratic. A hurricane such as Camille possessed an otherworldly power. A hurricane such as Katrina was so enormous that it almost defied comprehension, until well afterward, when scientists determined that it had two eyewalls, that in fact it made landfall as a hurricane within a hurricane, a ghastly Siamese twins of a hurricane. Then there was sodden Danny, lingering in Mobile Bay over an entire weekend like a house guest who soon wore out his welcome.
Danny may have been the soggiest hurricane in all of history, said Williams. A water gauge at Dauphin Island recorded 36 inches of rain during Danny, probably far short of what actually fell, said Williams. The 36 inches was collected during hurricane force winds, so the actual total was almost certainly greater and Doppler radar suggested an amount closer to 45 inches.
As for Katrina's double eye-walls, Williams said it is not unusual for an extremely powerful hurricane like Katrina to experience an ever-tightening eye until it begins to collapse while a new eye is formed with a bigger diameter. The ferocity of a Category 5 hurricane cannot be sustained indefinitely, he said. So do these raging engines wax and wane.
In the case of Katrina, said Williams, landfall occurred for the inner eye in west Mississippi while the outer eye passed over the Gulf Coast as far east as Pascagoula. Initially weather experts dismissed as hooey the claims of a Pascagoula emergency director who said he read two anemeters showing winds of 138 mph before they and the roof they were on blew away.
The double eyewalls, the concave coastline and the Category 5 water surge all conspired diabolically in Katrina to deliver a hellish wallop. Though Katrina in popular mythology has been defined as a New Orleans hurricane, it was in fact a Mississippi hurricane, said Williams. But for the breaching of the levees in New Orleans, the good times would've rolled right along in the "city that care forgot." The big hit on the Big Easy is yet to come, said Williams.
Another odd misfortune in Katrina's tidal wave of misfortune has to do with insurance, said Williams. According to the meteorologist, hurricane winds hit the coast four hours before the monstrous surge of water. Consequently, much of the initial property damage was caused by wind, not water. However, to the chagrin of policy holders, the evidence of wind damage was washed away in the surge. The system needs somehow to be tweaked to address that reality, he said.
Current research suggests that "collapsing cores" within hurricanes can deliver a Category 5-like punch in a restricted area where the surrounding area is generally experiencing Category 2 or 3 conditions. Williams said wind velocities are much greater at 1,500 feet than at the surface in a hurricane. As the hurricane collects water, winds at the upper levels are weighed down by the water and fall to earth so that a small 130 mph patch drops and obliterates a house while a nearby house suffers only a few lost shingles common in 80-85 mph winds.
Mobile's modern signature hurricane, Frederic in 1979, was a high Category 3, "pretty nasty," said Williams. With landfall just to Mobile's west, it was about as bad a hit as is possible for Mobile, he said. The city underwent a complete rewiring in the aftermath of Frederic, he said.
Between 1926 and 1979, Mobile basically enjoyed a hurricane-free existence.
Mobile had bad hurricanes in 1906 and 1916. In those days, there was no agonizing in advance of a hurricane because the storm itself announced its arrival. In 1906, Williams noted, there was no mention of an approaching hurricane in the newspaper the day before it hit.
Mobilians awoke, saw ominous signs in the sky and thought, "looks like we're in for a bad day," said Williams.
