Irene was a tropical storm _ not a hurricane _ when it made landfall in New Jersey in August, forecasters at the National Hurricane Center have determined after a review.
The deadly storm was a Category 1 hurricane when it made landfall Aug. 27 in North Carolina. The storm made landfall again Aug. 28 near Atlantic City, N.J., where forecasters had said it was a hurricane with 75 mph winds.
However, after reviewing their data, forecasters have determined that Irene had weakened to a tropical storm with winds around 69 mph when it crossed New Jersey's coast. Hurricanes have top winds of at least 74 mph.
"It's a very small change," said Eric Blake, a hurricane specialist at the hurricane center. "The difference residents would see is about the same. There's no perceivable difference."
Forecasters posted their report on Irene on Friday. The hurricane center occasionally upgrades or downgrades tropical storms as it reviews storm data at the end of the six-month hurricane season. In Irene's case, a review of the data supported downgrading the storm at the time it hit New Jersey, Blake said.
"Five-knot changes like that happen all the time. At this time, it just happened near land," Blake said.
Irene was one of the costliest storms in U.S. history. It caught much of the Eastern seaboard by surprise as it churned up the coast, prompting mass evacuations in New York City before it dumped torrential rains over parts of New England. Devastating flooding in Vermont damaged or destroyed hundreds of miles of roads, scores of bridges and hundreds of homes and left about a dozen communities cut off except for supply drops by National Guard helicopters.
The storm killed more than 50 people in the U.S., Caribbean and Canada.
The six-month Atlantic hurricane season that ended Nov. 30 produced 19 tropical storms, including seven hurricanes, making it one of the busiest seasons on record. It was the sixth straight year without a major hurricane making landfall in the U.S.
Hurricanes are considered major when they reach Category 3, with top winds of at least 111 mph. Storms are named when their winds reach speeds of at least 39 mph.
The 2011 season's storm totals include an upgrade of Tropical Storm Nate to hurricane status and the addition of an unnamed tropical storm that formed in early September over the open Atlantic between Bermuda and Nova Scotia.
The next Atlantic hurricane season begins June 1.
National Hurricane Center: http://www.nhc.noaa.gov/