WASHINGTON – If it seems as if more monster hurricanes, such as the soon-to-strike Frances, are swirling off the U.S. coast, you’re right. We’re in the midst of a record-breaking decade of hurricane activity.

And it’s likely to get worse, some experts predict.

The past nine years, from 1995 through 2003, mark the busiest, most intense nine-year storm period on record, based on the National Oceanic and Atmospheric Administration’s hurricane season index. The number takes into account how many storms develop, how strong their winds are and how long they last.

The so-called Accumulated Cyclone Energy index for the past nine years has averaged 139.6. That’s 50 percent higher than the 54-year average of 93.2 from 1950 through 2003. The increase comes despite low indexes for 1997 and 2002, both unusually mild years.

That means we’re experiencing more storms that are bigger and nastier.

Since 1995, there’s been an average of 13.3 named storms, 7.7 hurricanes and 3.6 major hurricanes (with winds of more than 111 mph) each year. That’s 50 percent higher than the 118-year average of 8.6 named storms, 5.1 hurricanes and two major hurricanes a year.

“1995 through now, apart from the El Nino years, is more active than anything in records,” Hugh Willoughby, a senior scientist at the International Hurricane Research Center in Miami, said as he packed his computer in plastic to protect it from Hurricane Frances. “It looks like there’s a trend of increasing hurricanes.”

This year is shaping up to be one of the worst.

As of Sept. 1, this season had had eight named storms, four of which became hurricanes and two of which (including Frances) are major hurricanes. And historically, most hurricanes form after Sept. 1.

“August has never seen eight named storms before,” said atmospheric scientist Chris Velden, of the University of Wisconsin in Madison. “We’re on a record pace.”

The scientist who pioneered hurricane-season forecasting, William Gray of Colorado State University in Fort Collins, forecast last month that 2004 would see 13 named storms, seven hurricanes and three major hurricanes.

He’ll update those predicted numbers, probably increasing them, on Friday, a university spokesman said.

Right now all the conditions are ripe for bigger and more frequent hurricanes, said Roger Pielke Sr., an atmospheric scientist at Colorado State.

Key ingredients for forming hurricanes are atmospheric disturbances – rainstorms that often chug off Africa’s Cape Verde and grow as they move west over the Atlantic – and the lack of upper-level winds that cut off storm tops, Pielke said. Those conditions are still favorable for more storms.

A major factor that allows hurricanes to grow bigger and stronger – such as Frances – is warm water.

“The Atlantic is a degree warmer than average this year. That may be a part of what’s causing what’s going on,” said Willoughby, who used to direct the federal government’s Hurricane Research Division.

And one weather condition that steers hurricanes – the Bermuda high-pressure ridge – is in a position that will direct storms into the U.S. mainland, not away as it has in past years, Pielke said.

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Just why it’s been so busy lately is widely debated. Some experts point to global warming, and others say it’s just part of natural cycles.

Hurricanes go through multi-decade cycles of many storms and few storms, Gray said in his most recent forecast. In the 1950s and 1960s, there were a lot of storms, then few from 1970 to 1994. Gray theorizes that it’s based on changes of temperature and salinity in the ocean on a massive scale that then changes atmospheric conditions.

The National Oceanic and Atmospheric Administration has computer models that predict that as the world warms, hurricanes will get stronger, but the models are geared more toward the future.

Willoughby sees what’s happening as a part of a normal cycle that could be juiced by warmer water.

While trends tend to be long-term, sometimes conditions change abruptly and few storms form, Pielke and Velden said.

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For more information, check out the following Web sites:

The National Hurricane Center:

http://www.nhc.noaa.gov/

NOAA’s calculation of the Accumulated Cyclone Energy index:

http://www.cpc.ncep.noaa.gov/products/outlooks/background(underscore)in formation.html

A chart of 54 years of Accumulated Cyclone Energy indices:

http://www.cpc.ncep.noaa.gov/products/outlooks/figure4.gif

William Gray’s hurricane season forecasts:

http://hurricane.atmos.colostate.edu/forecasts/

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(c) 2004, Knight Ridder/Tribune Information Services.

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GRAPHICS (from KRT Graphics, 202-383-6064): 20040902 HURRICANES, 20040902 Bahamas map, 20040902 Storm Frances

AP-NY-09-02-04 1839EDT