Story Highlights• 9 named storms, 5 hurricanes in 2006
• No U.S. hurricane landfall for first time since 2001
• 2006 quiet after 2004, 2005, but still at historical average
• El Nino helped prevent storms, forecasters say
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MIAMI, Florida (CNN) -- Defying predictions, the 2006 Atlantic hurricane season ended with a whimper rather than a bang on Thursday, without a single hurricane hitting U.S. shores.
Only three tropical storms made landfall, a welcome relief from the previous two years, when nearly a dozen hurricanes battered the country.
The sense of quiet was relative. Although 2006 might have seemed tame compared with the devastation of 2004 and 2005, the season's totals -- nine named storms, five hurricanes, two of them major -- were actually right at the historical average for the past 150 years, according to data from the National Hurricane Center.
This year's tropical activity fell well short of predictions made at the beginning of the season that called for an above-average number of storms -- although not as many as last year's record-shattering season of 28 named storms.
The forecasters' crystal balls were made cloudy by the unexpected formation of the El Nino phenomenon in the Pacific Ocean in midsummer, weather experts said. Even the most sophisticated computer models couldn't see El Nino coming to dampen tropical activity in the Atlantic.
"It turns out that El Nino developed more rapidly than expected, and the atmosphere responded quickly," said Gerry Bell of the National Oceanic and Atmospheric Administration's Climate Prediction Center. "So that really helped to offset the overall favorable conditions [for hurricanes] that we've had in place for more than the last decade."
An El Nino happens when waters warm in the Pacific, affecting the atmosphere and increasing westerly winds. As a result, Atlantic hurricanes are weakened and pushed away from the U.S. East Coast.
Four of this season's five hurricanes -- Florence, Gordon, Helene and Issac -- started to march westward across the Atlantic toward the United States, only to be turned northward and sent out to sea to dissipate.
Before the season began in June, the hurricane center predicted 13 to 16 named storms, with eight to 10 hurricanes, four to six of which could become major. In August, after the season got off to a slow start, that forecast was tweaked to 12 to 15 named storms, seven to nine hurricanes and three or four major hurricanes.
"This year, our August forecast was the first August forecast ever to over-forecast the activity," Bell said. "So this is not a common thing."
The U.S. mainland got through the entire seasons of 2001 and 2000 without a hurricane making landfall. That isn't common. During the past 100 seasons, Americans have lucked out and avoided a hurricane landfall just 18 times, according to National Hurricane Center data.
This year was also unusual because no tropical systems formed at all in October. That is the first time that has happened since 1994, according to the hurricane center.
Only three tropical systems affected the United States this year: Tropical Storm Alberto came ashore in Florida's Big Bend region in June, then moved north through Georgia and South Carolina; Tropical Storm Beryl brushed Cape Cod in July; and Tropical Storm Ernesto made landfalls in southern Florida on August 30 and along the North Carolina coast two days later.
Only Alberto hit the Gulf of Mexico this year, which was welcome news for residents of New Orleans and the Gulf Coast still trying to recover from 2005's one-two punch from hurricanes Katrina and Rita.
The most powerful hurricanes this year were Helene, whose maximum sustained winds reached 125 mph, and Gordon, with winds reaching 120 mph. Both were classified as Category 3 on the Saffir-Simpson scale, which rates the power of storms from Category 1 to Category 5.
By contrast, in 2005, three storms reached Category 5 -- Katrina, Rita and Wilma, the most intense hurricane ever recorded -- and two others reached Category 4.
But despite this year's respite, forecasters are quick to point out that hurricane activity moves in cycles and the Atlantic basin remains in a very active area that could last another 20 years.
From 1995 to 2005, the yearly average has been 15 named storms and eight hurricanes, four of them major -- substantially higher than what has been seen historically and during 2006.
CNN's Rob Marciano contributed to this report.
Tropical Storm Ernesto flooded parts of North Carolina in early September.