It's official: 2005 hurricanes blew records away

Season may yet have sting in the tail

By Manav Tanneeru
CNN

Though December storms are still a possibility, CNN meteorologist Chad Myers said, the hurricane season officially runs from June 1 to the end of November.

"The hurricane season is not an on and off switch. If the water is still warm enough, we could still get a tropical storm in December, and this could be one of those years where that could happen," Myers said. (Watch a look at worst year on record --2:27)

A day before the scheduled end of the season, Tropical Storm Epsilon formed over the central Atlantic Ocean.

Epsilon -- the fifth letter of the Greek alphabet used by forecasters since they ran out of their standard list of names -- is not expected to threaten land. (Full story)

Including Epsilon, there were 26 named storms this year, surpassing the record of 21 set in 1933. Thirteen of the storms were hurricanes, edging by one the previous record set in 1969. Seven of the hurricanes were considered major. (Deadliest, costliest and other hurricane facts)

The normal seasonal average is 10 named storms, six hurricanes and two major hurricanes, according to the National Hurricane Center.

Three of the hurricanes in the 2005 season reached Category 5 status, meaning they had wind speeds greater than 155 mph at some point during the arc of the storm.

"We've had two Category 5 storms in several seasons, but we've never had three," said Steve Kiser, a tropical cyclone program manger at the National Weather Service.

"We also set some records for the lowest pressure levels, which is an indication of a storm's intensity. So, certainly this year, we had some very intense, very strong storms."

Two of the three storms that struck the United States -- Katrina and Wilma -- caused severe damage.

Hurricane Katrina, whose initial readings place it among the most intense storms since 1900, cut a wide swath of destruction across the Gulf Coast states of Louisiana, Mississippi and Alabama.

Two months after Katrina hit the Gulf Coast, the death toll stood at 1,289. Thousands were displaced to shelters around the country as entire communities and cities were flattened by the storm.

The Federal Emergency Management Agency said insurance claims totaled some $23 billion. Reconstruction costs are estimated to be at least $200 billion, making Katrina the costliest storm in history.

Hurricane Wilma, which passed over South Florida, is estimated to have caused between $6 billion and $9 billion in insured losses, according to AIR Worldwide, a firm that advises the insurance industry. If the estimates prove true, Wilma would rank among the top three costliest storms on record.

"Needless to say, it's been six long months for people living along the East Coast and the Gulf Coast," retired Air Force Brig. Gen. David L. Johnson, director of the National Weather Service, said.

Looking for a reason

Climatologists believe the 2005 hurricane season fell at the peak of a cycle that alternates between low-intensity and high-intensity seasons.

"The climatologists have gone back into the history books to look at these cycles and typically they're anywhere from 20 to 30 years," Kiser said.

"If we look in the 1970s and 1980s, we had a low period, and now in the mid-90s to the current season, we're in the high period," he said. "This [cycle] began in 1995 and since then, nine of the 11 tropical cyclone seasons have been above normal."

CNN's Myers cautioned there is not enough historical evidence to fully support the idea. "There certainly is the possibility of cycle," he said.

"[But] the problem with all of this is that we don't know what the hurricane seasons were like 150 years ago. ... It's hard to say with the shortness of data that we have, our spectrum is so small, and we've only been really studying this for 50 years, or maybe 100 years tops."

Experts and observers, however, can concretely point to several weather conditions that contributed to the intensity of the season.

Atmospheric conditions like wind speeds and upper-level steering flows were conducive to strengthening storms this year, Kiser said. In other words, winds were generally moving in the same direction and typically with the same speed, helping storms retain their shape and uniformity.

"What is not conducive for hurricanes or will tend to weaken them is that at one level, you have winds from the south, and at another level, you have winds from the north. Additionally, you could have winds at 5 mph at one level, and winds at 50 mph at another level," Kiser said.

Warm water, fuel for a tropical storm, was also easily available this year because of changes in sea surface temperatures. "Just as we get seasonal changes in air temperature over the longer period, you can get changes within the sea surface temperature, and that's part of this multidecadal pattern that we see," Kiser said.

Myers and Kiser had somewhat differing perspectives over how much global warming may have contributed to this season.

"Global warming is a problem well-known by very many scientists and it's a problem we have to deal with," Kiser said. "However, I think basically we feel that the number and the intensity [of storms this year are] more related to this high-activity period."

Myers said it is possible global warming may have warmed the waters by a degree or two. "It could be half a degree for all we know [and] that little bit of 'oomph' may have taken a Category 1 storm and made it to a Category 2. It may have taken a storm that was just a tropical storm, and made it into a hurricane," he said.

"There's no way to put 100 percent credence on any one thing to explain the season," Myers said. "You can't make chicken soup from chicken alone. You have to have other parts in the stock. It could have been the cycle in addition to the warm water temperatures in addition to the lack of an El Nino."

An El Nino occurs when the ocean-atmosphere system in the tropical Pacific Ocean is disrupted.

There is a fear next year's season could bring much of the same as 2005.

"If we are truly in a cycle, next year we probably will have between 15 and 20 cycles. If we are in a cycle being enhanced by global warming, we may have 24 storms again," Myers said.

"There's also the chance the cycle ends next year, and it just shuts itself off. We don't think that's going to happen, we think we're at the beginning of the up trend, and not the down trend.