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2 storms, similar paths, 2 fates

Hurricanes Wilma and Mitch shared much, but one was far larger, the other far deadlier.

By DAVID ADAMS
Published November 1, 2005


MIAMI - They were almost identical twins - born eight years apart.

Each very different, yet they held so much in common: big, bad Wilma and deadly Mitch.

Both hurricanes have entered the infamous annals of Caribbean basin history, masters in their own terrifying meteorological categories. Both late season October storms, they grew into Category 5 monsters, following similar tracks through the western Caribbean - typical for this time of year.

Unlike early storms in the eastern Caribbean that often wheel away from Florida and burn out over the Atlantic, late storms are trapped in the Caribbean.

"Somebody is going to get hit, and hit hard," said Christopher Landsea, science and operations officer with the National Hurricane Center who runs the Hurricane Database Re-Analysis project, which compares the performance of storms.

The destructive paths of Wilma and Mitch were similar, but what a difference a few degrees of latitude can make. Wilma missed the heart of Central America, home to some of the hemisphere's poorest and most weather-vulnerable populations. Instead, relatively wealthy areas of South Florida and Mexico's Yucatan peninsula bore the brunt. Economic damage will be in the billions, but few lives were lost.

By comparison, in 1998 Hurricane Mitch laid waste to the fragile agricultural economies of Honduras and Nicaragua, killing more than 9,000 people. Its force was largely spent by the time it left the Yucatan and meandered its way over to southwest Florida, cutting across the state from Naples to the east coast.

If Mitch was the deadliest storm in the Atlantic in the last two centuries (since the "Great Hurricane" of 1780 that killed 22,000 people in the eastern Caribbean), Wilma will be remembered as the strongest and largest hurricane recorded, a gargantuan 180 miles wide with winds topping out at 165 mph.

At its height, Wilma's barometric pressure - a measure of a storm's strength - dropped to 882 millibars, the lowest on record in the Atlantic basin. The lower the pressure, the stronger the storm. In its day, Mitch's barometric pressure of 905 millibars ranked it as the strongest October hurricane, and the fourth most powerful Atlantic storm of all time. At its height it also packed sustained winds of 180 mph, and gusts well over 200 mph.

Wilma and Mitch both formed in the western Caribbean, where sea surface temperatures are most favorable for the genesis of storms at this time of year. Researchers at the National Hurricane Center say that sea temperatures this year are 1 to 3 degrees warmer than usual. They also attribute this year's highly active season to the absence of "vertical wind shear" - the interaction of a hurricane with surrounding wind systems that can disrupt its development.

"We see greater wind circulation and less wind shear at this time of year in the Caribbean," Landsea said. "These low-level spiraling winds can provide the initial spark."

Upper atmosphere steering currents that form over the United States at this time of year usually serve as a buffer from major storms, pushing them away. But if they find a gap, watch out.

Wilma was still only a tropical storm when it brushed Haiti, Cuba and Jamaica on Oct 16 and 17. At least 11 people were killed in Haiti by floods and landslides. In Jamaica, Wilma was blamed for one death after heavy rainfall flooded several low-lying communities.

In Havana, a huge sea surge and 20-foot waves caused flooding along the famous seafront.

But as Wilma passed the Cayman Islands on the morning of Oct. 18, it went through a sudden transformation, mushrooming into a Category 5 hurricane - winds over 155 mph.

Two days later it slammed into Mexico's tourist-packed Yucatan peninsula. Hotels were hammered and will likely be closed until the new year. One of the Caribbean's best beaches was stripped of its powdery white sand. Reconstruction costs are estimated at almost $3-billion, according to Mexico's government. Eight lives were lost.

Wilma briefly lost strength before re-energizing over the warm waters of the Gulf of Mexico. It hit Florida as a Category 3 - winds from 111 to 130 mph. Florida sustained less structural damage than the Yucatan, but a disabled power grid brought an economy to a halt.

Mitch did no damage before reaching Central America. It became a hurricane early on Oct. 24 about 255 miles south-southwest of Kingston, Jamaica.

Mitch moved westward toward the northern coast of Honduras. Waves reportedly reached as high as 44 feet, according to one wave model. The Miami-based schooner Fantome disappeared. Thirty-one members of the crew were presumed killed.

Moving at a painfully slow pace, Mitch drifted over the mountainous interior of Honduras, depositing an enormous watery load. Rainfall was reported as high as 35 inches over a 24 hour period in some areas. The resulting floods and mudslides swept away roads and bridges across Honduras.

Mitch made landfall near Naples on the morning of Nov. 5 with estimated maximum sustained winds of 63.4 mph, barely 10 mph short of hurricane strength.

Several tornadoes in Florida injured 65 people and damaged or destroyed 645 homes. Across South Florida, some 100,000 customers lost electrical power. Two people drowned near Dry Tortugas and another person died in an accident on a slick highway.

In Wilma's case, the storm made a faster turn eastward thanks to a break in the "subtropical ridge," the high pressure atmospheric buffer over the United States, allowing it to seek new energy from warm waters off Cuba. By the time it reached southwest Florida, it was packing twice the strength of Mitch.

Last weekend forecasters had their eyes on Hurricane Beta as it approached the west coast of Nicaragua. As expected, it became a Category 2, with winds between 96 and 110 mph, before it came ashore late Sunday.

While it did bring heavy rainfall, it did not pose a major threat. Its eye was estimated at barely 15 miles wide - a mere weakling by the standards of Wilma and Mitch.

--David Adams can be contacted at dadams@sptimes.com